diff --git a/wp-admin/async-upload.php b/wp-admin/async-upload.php
index 4c225c4fda..8ee85fc1f8 100644
--- a/wp-admin/async-upload.php
+++ b/wp-admin/async-upload.php
@@ -25,7 +25,7 @@ if ( !current_user_can('upload_files') )
 	wp_die(__('You do not have permission to upload files.'));
 
 // just fetch the detail form for that attachment
-if ( ($id = intval($_REQUEST['attachment_id'])) && $_REQUEST['fetch'] ) {
+if ( isset($_REQUEST['attachment_id']) && ($id = intval($_REQUEST['attachment_id'])) && $_REQUEST['fetch'] ) {
 	if ( 2 == $_REQUEST['fetch'] ) {
 		add_filter('attachment_fields_to_edit', 'media_single_attachment_fields_to_edit', 10, 2);
 		echo get_media_item($id, array( 'send' => false, 'delete' => false ));
diff --git a/wp-admin/edit-link-form.php b/wp-admin/edit-link-form.php
index d1b88ec73b..6bbeeb080c 100644
--- a/wp-admin/edit-link-form.php
+++ b/wp-admin/edit-link-form.php
@@ -343,12 +343,7 @@ require_once ('admin-header.php');
 <div class="wrap">
 <h2><?php echo wp_specialchars( $title ); ?></h2> 
 
-<?php
-$link_added = ( isset($_GET['added']) && '' != $_POST['link_name'] ) ?
-	'<div id="message" class="updated fade"><p>' . __('Link added.') . '</p></div>' : '';
-?>
-
-<?php if ( isset( $_GET['added'] ) && '' != $_POST['link_name']) : ?>
+<?php if ( isset( $_GET['added'] ) ) : ?>
 <div id="message" class="updated fade"><p><?php _e('Link added.'); ?></p></div>
 <?php endif; ?>
 
diff --git a/wp-admin/includes/bookmark.php b/wp-admin/includes/bookmark.php
index 8ee7d39b21..88bd03035c 100644
--- a/wp-admin/includes/bookmark.php
+++ b/wp-admin/includes/bookmark.php
@@ -34,7 +34,7 @@ function edit_link( $link_id = '' ) {
 	$_POST['link_name'] = wp_specialchars( $_POST['link_name'] );
 	$_POST['link_image'] = wp_specialchars( $_POST['link_image'] );
 	$_POST['link_rss'] = clean_url($_POST['link_rss']);
-	if ( 'N' != $_POST['link_visible'] )
+	if ( !isset($_POST['link_visible']) || 'N' != $_POST['link_visible'] )
 		$_POST['link_visible'] = 'Y';
 
 	if ( !empty( $link_id ) ) {
@@ -176,7 +176,7 @@ function wp_insert_link( $linkdata, $wp_error = false ) {
 		$link_rel = '';
 
 	// Make sure we set a valid category
-	if ( 0 == count( $link_category ) || !is_array( $link_category ) ) {
+	if ( ! isset( $link_category ) ||0 == count( $link_category ) || !is_array( $link_category ) ) {
 		$link_category = array( get_option( 'default_link_category' ) );
 	}
 
@@ -265,4 +265,4 @@ function wp_update_link( $linkdata ) {
 	return wp_insert_link( $linkdata );
 }
 
-?>
\ No newline at end of file
+?>
diff --git a/wp-admin/includes/dashboard.php b/wp-admin/includes/dashboard.php
index cd621cfd68..51ddbbf0d2 100644
--- a/wp-admin/includes/dashboard.php
+++ b/wp-admin/includes/dashboard.php
@@ -177,11 +177,13 @@ function wp_dashboard_right_now() {
 	echo "\n\t".'<tr class="first">';
 
 	// Posts
-	$num = number_format_i18n( $num_posts->publish );
+	$num = isset($num_posts->publish) ? number_format_i18n( $num_posts->publish ) : 0;
 	if ( current_user_can( 'edit_posts' ) )
-		$num = "<a href='edit.php'>$num</a>";
-	echo '<td class="first b b-posts">'.$num.'</td>';
-	echo '<td class="t posts">' . __ngettext( 'Post', 'Posts', $num_posts->publish ) . '</td>';
+		$text = "<a href='edit.php'>$num</a>";
+	else
+		$text = $num;
+	echo '<td class="first b b-posts">' . $text . '</td>';
+	echo '<td class="t posts">' . __ngettext( 'Post', 'Posts', $num ) . '</td>';
 	/* TODO: Show status breakdown on hover
 	if ( $can_edit_pages && !empty($num_pages->publish) ) { // how many pages is not exposed in feeds.  Don't show if !current_user_can
 		$post_type_texts[] = '<a href="edit-pages.php">'.sprintf( __ngettext( '%s page', '%s pages', $num_pages->publish ), number_format_i18n( $num_pages->publish ) ).'</a>';
diff --git a/wp-admin/includes/file.php b/wp-admin/includes/file.php
index a0cf49a54f..9c8ec0b620 100644
--- a/wp-admin/includes/file.php
+++ b/wp-admin/includes/file.php
@@ -224,6 +224,9 @@ function wp_handle_upload( &$file, $overrides = false, $time = null ) {
 	// You may define your own function and pass the name in $overrides['upload_error_handler']
 	$upload_error_handler = 'wp_handle_upload_error';
 
+	// You may define your own function and pass the name in $overrides['unique_filename_callback']
+	$unique_filename_callback = null;
+
 	// $_POST['action'] must be set and its value must equal $overrides['action'] or this:
 	$action = 'wp_handle_upload';
 
diff --git a/wp-admin/includes/media.php b/wp-admin/includes/media.php
index 6e123d566d..551720a7b9 100644
--- a/wp-admin/includes/media.php
+++ b/wp-admin/includes/media.php
@@ -209,7 +209,7 @@ function media_handle_upload($file_id, $post_id, $post_data = array()) {
 	), $post_data );
 
 	// Save the data
-	$id = wp_insert_attachment($attachment, $file, $post_parent);
+	$id = wp_insert_attachment($attachment, $file, $post_id);
 	if ( !is_wp_error($id) ) {
 		wp_update_attachment_metadata( $id, wp_generate_attachment_metadata( $id, $file ) );
 	}
@@ -989,10 +989,8 @@ function get_media_items( $post_id, $errors ) {
 				$attachments[$attachment->ID] = $attachment;
 	}
 
-	if ( empty($attachments) )
-		return '';
-
-	foreach ( $attachments as $id => $attachment )
+	$output = '';
+	foreach ( (array) $attachments as $id => $attachment )
 		if ( $item = get_media_item( $id, array( 'errors' => isset($errors[$id]) ? $errors[$id] : null) ) )
 			$output .= "\n<div id='media-item-$id' class='media-item child-of-$attachment->post_parent preloaded'><div class='progress'><div class='bar'></div></div><div id='media-upload-error-$id'></div><div class='filename'></div>$item\n</div>";
 
@@ -1039,6 +1037,7 @@ function get_media_item( $attachment_id, $args = null ) {
 		$tags = attribute_escape(join(', ', $tags));
 	}
 
+	$type = '';
 	if ( isset($post_mime_types) ) {
 		$keys = array_keys(wp_match_mime_types(array_keys($post_mime_types), $post->post_mime_type));
 		$type = array_shift($keys);
diff --git a/wp-admin/includes/post.php b/wp-admin/includes/post.php
index 62ed101302..7c44c40d92 100644
--- a/wp-admin/includes/post.php
+++ b/wp-admin/includes/post.php
@@ -153,18 +153,20 @@ function edit_post( $post_data = null ) {
 	if ( is_wp_error($post_data) )
 		wp_die( $post_data->get_error_message() );
 
-	switch ( $post_data['visibility'] ) {
-		case 'public' :
-			unset( $post_data['post_password'] );
-			break;
-		case 'password' :
-			unset( $post_data['sticky'] );
-			break;
-		case 'private' :
-			$post_data['post_status'] = 'private';
-			$post_data['post_password'] = '';
-			unset( $post_data['sticky'] );
-			break;
+	if ( isset($post_data['visibility']) ) {
+		switch ( $post_data['visibility'] ) {
+			case 'public' :
+				unset( $post_data['post_password'] );
+				break;
+			case 'password' :
+				unset( $post_data['sticky'] );
+				break;
+			case 'private' :
+				$post_data['post_status'] = 'private';
+				$post_data['post_password'] = '';
+				unset( $post_data['sticky'] );
+				break;
+		}
 	}
 
 	// Meta Stuff
@@ -337,6 +339,7 @@ function get_default_post_to_edit() {
 	$post->post_name = '';
 	$post->post_author = '';
 	$post->post_date = '';
+	$post->post_password = '';
 	$post->post_status = 'draft';
 	$post->post_type = 'post';
 	$post->to_ping = '';
@@ -456,18 +459,20 @@ function wp_write_post() {
 	if ( is_wp_error($translated) )
 		return $translated;
 
-	switch ( $_POST['visibility'] ) {
-		case 'public' :
-			$_POST['post_password'] = '';
-			break;
-		case 'password' :
-			unset( $_POST['sticky'] );
-			break;
-		case 'private' :
-			$_POST['post_status'] = 'private';
-			$_POST['post_password'] = '';
-			unset( $_POST['sticky'] );
-			break;
+	if ( isset($_POST['visibility']) ) {
+		switch ( $_POST['visibility'] ) {
+			case 'public' :
+				$_POST['post_password'] = '';
+				break;
+			case 'password' :
+				unset( $_POST['sticky'] );
+				break;
+			case 'private' :
+				$_POST['post_status'] = 'private';
+				$_POST['post_password'] = '';
+				unset( $_POST['sticky'] );
+				break;
+		}
 	}
 
 	// Create the post.
diff --git a/wp-admin/user-new.php b/wp-admin/user-new.php
index 126e10d09f..5fc5f60326 100644
--- a/wp-admin/user-new.php
+++ b/wp-admin/user-new.php
@@ -22,12 +22,12 @@ if ( isset($_REQUEST['action']) && 'adduser' == $_REQUEST['action'] ) {
 		wp_die(__('You can&#8217;t create users.'));
 
 	$user_id = add_user();
-	$update = 'add';
-	if ( is_wp_error( $user_id ) )
+
+	if ( is_wp_error( $user_id ) ) {
 		$add_user_errors = $user_id;
-	else {
+	} else {
 		$new_user_login = apply_filters('pre_user_login', sanitize_user(stripslashes($_REQUEST['user_login']), true));
-		$redirect = add_query_arg( array('usersearch' => urlencode($new_user_login), 'update' => $update), $redirect );
+		$redirect = 'users.php?usersearch='. urlencode($new_user_login) . '&update=add';
 		wp_redirect( $redirect . '#user-' . $user_id );
 		die();
 	}
@@ -78,6 +78,15 @@ if ( ! empty($messages) ) {
 ?>
 <form action="#add-new-user" method="post" name="adduser" id="adduser" class="add:users: validate">
 <?php wp_nonce_field('add-user') ?>
+<?php
+//Load up the passed data, else set to a default.
+foreach ( array('user_login' => 'login', 'first_name' => 'firstname', 'last_name' => 'lastname',
+				'email' => 'email', 'url' => 'uri', 'role' => 'role') as $post_field => $var ) {
+	$var = "new_user_$var";
+	if ( ! isset($$var) )
+		$$var = isset($_POST[$post_field]) ? stripslashes($_POST[$post_field]) : '';
+}
+?>
 <table class="form-table">
 	<tr class="form-field form-required">
 		<th scope="row"><label for="user_login"><?php _e('Username (required)') ?></label><input name="action" type="hidden" id="action" value="adduser" /></th>
@@ -114,7 +123,7 @@ if ( ! empty($messages) ) {
 		<td><select name="role" id="role">
 			<?php
 			if ( !$new_user_role )
-				$new_user_role = $current_role ? $current_role : get_option('default_role');
+				$new_user_role = !empty($current_role) ? $current_role : get_option('default_role');
 			wp_dropdown_roles($new_user_role);
 			?>
 			</select>
@@ -122,7 +131,6 @@ if ( ! empty($messages) ) {
 	</tr>
 </table>
 <p class="submit">
-	<?php echo $referer; ?>
 	<input name="adduser" type="submit" id="addusersub" class="button" value="<?php _e('Add User') ?>" />
 </p>
 </form>
diff --git a/wp-includes/bookmark.php b/wp-includes/bookmark.php
index c16721d9f8..4a031ee5b4 100644
--- a/wp-includes/bookmark.php
+++ b/wp-includes/bookmark.php
@@ -265,15 +265,22 @@ function sanitize_bookmark($bookmark, $context = 'display') {
 		'link_description', 'link_visible', 'link_owner', 'link_rating', 'link_updated',
 		'link_rel', 'link_notes', 'link_rss', );
 
-	$do_object = false;
-	if ( is_object($bookmark) )
+	if ( is_object($bookmark) ) {
 		$do_object = true;
+		$link_id = $bookmark->link_id;
+	} else {
+		$do_object = false;
+		$link_id = $bookmark['link_id'];
+	}
 
 	foreach ( $fields as $field ) {
-		if ( $do_object )
-			$bookmark->$field = sanitize_bookmark_field($field, $bookmark->$field, $bookmark->link_id, $context);
-		else
-			$bookmark[$field] = sanitize_bookmark_field($field, $bookmark[$field], $bookmark['link_id'], $context);
+		if ( $do_object ) {
+			if ( isset($bookmark->$field) )
+				$bookmark->$field = sanitize_bookmark_field($field, $bookmark->$field, $link_id, $context);
+		} else {
+			if ( isset($bookmark[$field]) )
+				$bookmark[$field] = sanitize_bookmark_field($field, $bookmark[$field], $link_id, $context);
+		}
 	}
 
 	return $bookmark;
diff --git a/wp-includes/post.php b/wp-includes/post.php
index 8d64004b65..f72c44fc22 100644
--- a/wp-includes/post.php
+++ b/wp-includes/post.php
@@ -1677,6 +1677,7 @@ function wp_set_post_tags( $post_id = 0, $tags = '', $append = false ) {
 	if ( empty($tags) )
 		$tags = array();
 	$tags = (is_array($tags)) ? $tags : explode( ',', trim($tags, " \n\t\r\0\x0B,") );
+	$tags = array_map('trim', $tags); //Trim whitespace from around the tags.
 	wp_set_object_terms($post_id, $tags, 'post_tag', $append);
 }
 
@@ -2158,8 +2159,10 @@ function &get_pages($args = '') {
 
 	$pages = $wpdb->get_results($query);
 
-	if ( empty($pages) )
-		return apply_filters('get_pages', array(), $r);
+	if ( empty($pages) ) {
+		$page = apply_filters('get_pages', array(), $r);
+		return $pages;
+	}
 
 	// Update cache.
 	update_page_cache($pages);
@@ -2261,7 +2264,7 @@ function wp_insert_attachment($object, $file = false, $parent = 0) {
 	extract($object, EXTR_SKIP);
 
 	// Make sure we set a valid category
-	if (0 == count($post_category) || !is_array($post_category)) {
+	if ( !isset($post_category) || 0 == count($post_category) || !is_array($post_category)) {
 		$post_category = array(get_option('default_category'));
 	}
 
@@ -2272,10 +2275,12 @@ function wp_insert_attachment($object, $file = false, $parent = 0) {
 	$post_status = 'inherit';
 
 	// Are we updating or creating?
-	$update = false;
 	if ( !empty($ID) ) {
 		$update = true;
 		$post_ID = (int) $ID;
+	} else {
+		$update = false;
+		$post_ID = 0;
 	}
 
 	// Create a valid post name.
@@ -3241,8 +3246,8 @@ function _wp_post_revision_fields( $post = null, $autosave = false ) {
 	$return['post_status']   = 'inherit';
 	$return['post_type']     = 'revision';
 	$return['post_name']     = $autosave ? "$post[ID]-autosave" : "$post[ID]-revision";
-	$return['post_date']     = $post['post_modified'];
-	$return['post_date_gmt'] = $post['post_modified_gmt'];
+	$return['post_date']     = isset($post['post_modified']) ? $post['post_modified'] : '';
+	$return['post_date_gmt'] = isset($post['post_modified_gmt']) ? $post['post_modified_gmt'] : '';
 
 	return $return;
 }
diff --git a/wp-includes/registration.php b/wp-includes/registration.php
index 591aa9691c..aee3ae149f 100644
--- a/wp-includes/registration.php
+++ b/wp-includes/registration.php
@@ -164,6 +164,15 @@ function wp_insert_user($userdata) {
 	if ( empty($use_ssl) )
 		$use_ssl = 0;
 
+	if ( empty($jabber) )
+		$jabber = '';
+
+	if ( empty($aim) )
+		$aim = '';
+
+	if ( empty($yim) )
+		$yim = '';
+
 	if ( empty($user_registered) )
 		$user_registered = gmdate('Y-m-d H:i:s');
 
diff --git a/wp-includes/rss.php b/wp-includes/rss.php
index e3ffb19266..0d70fba2c6 100644
--- a/wp-includes/rss.php
+++ b/wp-includes/rss.php
@@ -459,7 +459,7 @@ function fetch_rss ($url) {
 		// setup headers
 		if ( $cache_status == 'STALE' ) {
 			$rss = $cache->get( $url );
-			if ( $rss->etag and $rss->last_modified ) {
+			if ( isset($rss->etag) and $rss->last_modified ) {
 				$request_headers['If-None-Match'] = $rss->etag;
 				$request_headers['If-Last-Modified'] = $rss->last_modified;
 			}
@@ -564,7 +564,7 @@ function _response_to_rss ($resp) {
 	$rss = new MagpieRSS( $resp->results );
 
 	// if RSS parsed successfully
-	if ( $rss && !$rss->ERROR) {
+	if ( $rss && (!isset($rss->ERROR) || !$rss->ERROR) ) {
 
 		// find Etag, and Last-Modified
 		foreach( (array) $resp->headers as $h) {
diff --git a/wp-login.php b/wp-login.php
index 6dc6d769f2..a59463ca30 100644
--- a/wp-login.php
+++ b/wp-login.php
@@ -294,16 +294,19 @@ case 'retrievepassword' :
 		}
 	}
 
-	if ( 'invalidkey' == $_GET['error'] ) $errors->add('invalidkey', __('Sorry, that key does not appear to be valid.'));
+	if ( isset($_GET['error']) && 'invalidkey' == $_GET['error'] ) $errors->add('invalidkey', __('Sorry, that key does not appear to be valid.'));
 
 	do_action('lost_password');
 	login_header(__('Lost Password'), '<p class="message">' . __('Please enter your username or e-mail address. You will receive a new password via e-mail.') . '</p>', $errors);
+
+	$user_login = isset($_POST['user_login']) ? stripslashes($_POST['user_login']) : '';
+
 ?>
 
 <form name="lostpasswordform" id="lostpasswordform" action="<?php echo site_url('wp-login.php?action=lostpassword', 'login_post') ?>" method="post">
 	<p>
 		<label><?php _e('Username or E-mail:') ?><br />
-		<input type="text" name="user_login" id="user_login" class="input" value="<?php echo attribute_escape(stripslashes($_POST['user_login'])); ?>" size="20" tabindex="10" /></label>
+		<input type="text" name="user_login" id="user_login" class="input" value="<?php echo attribute_escape($user_login); ?>" size="20" tabindex="10" /></label>
 	</p>
 <?php do_action('lostpassword_form'); ?>
 	<p class="submit"><input type="submit" name="wp-submit" id="wp-submit" value="<?php _e('Get New Password'); ?>" tabindex="100" /></p>