diff --git a/src/java/org/apache/poi/ss/formula/OperationEvaluationContext.java b/src/java/org/apache/poi/ss/formula/OperationEvaluationContext.java
index ce918926ca..cc590772de 100644
--- a/src/java/org/apache/poi/ss/formula/OperationEvaluationContext.java
+++ b/src/java/org/apache/poi/ss/formula/OperationEvaluationContext.java
@@ -94,7 +94,11 @@ public final class OperationEvaluationContext {
 		if (externalSheet == null || externalSheet.getWorkbookName() == null) {
 			// sheet is in same workbook
 			targetEvaluator = _bookEvaluator;
-			otherFirstSheetIndex = _workbook.getSheetIndex(externalSheet.getSheetName());
+			if(externalSheet == null) {
+			    otherFirstSheetIndex = 0;
+			} else {
+			    otherFirstSheetIndex = _workbook.getSheetIndex(externalSheet.getSheetName());
+			}
 			
 			if (externalSheet instanceof ExternalSheetRange) {
 			    String lastSheetName = ((ExternalSheetRange)externalSheet).getLastSheetName();
diff --git a/src/testcases/org/apache/poi/hssf/usermodel/TestBugs.java b/src/testcases/org/apache/poi/hssf/usermodel/TestBugs.java
index f472e3d1d4..92661f8aee 100644
--- a/src/testcases/org/apache/poi/hssf/usermodel/TestBugs.java
+++ b/src/testcases/org/apache/poi/hssf/usermodel/TestBugs.java
@@ -2846,4 +2846,22 @@ public final class TestBugs extends BaseTestBugzillaIssues {
 
         wb.close();
     }
+    
+    @Test
+    public void test57925() throws IOException {
+        Workbook wb = HSSFTestDataSamples.openSampleWorkbook("57925.xls");
+        
+        wb.getCreationHelper().createFormulaEvaluator().evaluateAll();
+        
+        for(int i = 0;i < wb.getNumberOfSheets();i++) {
+            Sheet sheet = wb.getSheetAt(i);
+            for(Row row : sheet) {
+                for(Cell cell : row) {
+                    new DataFormatter().formatCellValue(cell);
+                }
+            }
+        }
+        
+        wb.close();
+    }
 }
diff --git a/test-data/spreadsheet/57925.xls b/test-data/spreadsheet/57925.xls
new file mode 100644
index 0000000000..ef13551ff4
Binary files /dev/null and b/test-data/spreadsheet/57925.xls differ