diff --git a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/editor/CElementHyperlinkDetector.java b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/editor/CElementHyperlinkDetector.java
index 8cb89d255b1..5d967d3bbb3 100644
--- a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/editor/CElementHyperlinkDetector.java
+++ b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/editor/CElementHyperlinkDetector.java
@@ -89,19 +89,21 @@ public class CElementHyperlinkDetector implements IHyperlinkDetector {
 		try {
 			IStatus status= ASTProvider.getASTProvider().runOnAST(workingCopy, ASTProvider.WAIT_YES, null, new ASTRunnable() {
 				public IStatus runOnAST(ILanguage lang, IASTTranslationUnit ast) {
-					IASTName[] selectedNames= 
-						lang.getSelectedNames(ast, selection.getOffset(), selection.getLength());
+					if (ast != null) {
+						IASTName[] selectedNames= 
+							lang.getSelectedNames(ast, selection.getOffset(), selection.getLength());
 
-					IRegion linkRegion;
-					if(selectedNames.length > 0 && selectedNames[0] != null) { // found a name
-						linkRegion = new Region(selection.getOffset(), selection.getLength());
-					}
-					else { // check if we are in an include statement
-						linkRegion = matchIncludeStatement(ast, selection);
-					}
+						IRegion linkRegion;
+						if(selectedNames.length > 0 && selectedNames[0] != null) { // found a name
+							linkRegion = new Region(selection.getOffset(), selection.getLength());
+						}
+						else { // check if we are in an include statement
+							linkRegion = matchIncludeStatement(ast, selection);
+						}
 
-					if(linkRegion != null)
-						result[0]= new CElementHyperlink(linkRegion, openAction);
+						if(linkRegion != null)
+							result[0]= new CElementHyperlink(linkRegion, openAction);
+					}
 					return Status.OK_STATUS;
 				}
 			});
diff --git a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/editor/ToggleSourceAndHeaderAction.java b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/editor/ToggleSourceAndHeaderAction.java
index 0b0d0eb4bcc..be517f4ea53 100644
--- a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/editor/ToggleSourceAndHeaderAction.java
+++ b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/editor/ToggleSourceAndHeaderAction.java
@@ -7,6 +7,7 @@
  *
  * Contributors:
  *     Anton Leherbauer (Wind River Systems) - initial API and implementation
+ *     Markus Schorn (Wind River Systems)
  *******************************************************************************/
 
 package org.eclipse.cdt.internal.ui.editor;
@@ -104,11 +105,13 @@ public class ToggleSourceAndHeaderAction extends TextEditorAction {
 			shouldVisitDeclarators= true;
 		}
 		public IStatus runOnAST(ILanguage lang, IASTTranslationUnit ast) {
-			fIndex= ast.getIndex();
-			fFilePath= Path.fromOSString(ast.getFilePath());
-			fMap= new HashMap();
-			if (fIndex != null) {
-				ast.accept(this);
+			if (ast != null) {
+				fIndex= ast.getIndex();
+				fFilePath= Path.fromOSString(ast.getFilePath());
+				fMap= new HashMap();
+				if (fIndex != null) {
+					ast.accept(this);
+				}
 			}
 			return Status.OK_STATUS;
 		}
diff --git a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/search/PDOMSearchTextSelectionQuery.java b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/search/PDOMSearchTextSelectionQuery.java
index c375c34a209..72baaecb48f 100644
--- a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/search/PDOMSearchTextSelectionQuery.java
+++ b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/search/PDOMSearchTextSelectionQuery.java
@@ -6,8 +6,8 @@
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
- * QNX - Initial API and implementation
- * Markus Schorn (Wind River Systems)
+ *    QNX - Initial API and implementation
+ *    Markus Schorn (Wind River Systems)
  *******************************************************************************/
 
 package org.eclipse.cdt.internal.ui.search;
@@ -48,12 +48,14 @@ public class PDOMSearchTextSelectionQuery extends PDOMSearchQuery {
 	protected IStatus runWithIndex(final IIndex index, IProgressMonitor monitor) {
 		return ASTProvider.getASTProvider().runOnAST(tu, ASTProvider.WAIT_YES, monitor, new ASTRunnable() {
 			public IStatus runOnAST(ILanguage language, IASTTranslationUnit ast) throws CoreException {
-				IASTName[] names = language.getSelectedNames(ast, selection.getOffset(), selection.getLength());
-				if (names != null) {
-					for (int i = 0; i < names.length; ++i) {
-						IBinding binding = names[i].resolveBinding();
-						if (binding != null)
-							createMatches(index, binding);
+				if (ast != null) {
+					IASTName[] names = language.getSelectedNames(ast, selection.getOffset(), selection.getLength());
+					if (names != null) {
+						for (int i = 0; i < names.length; ++i) {
+							IBinding binding = names[i].resolveBinding();
+							if (binding != null)
+								createMatches(index, binding);
+						}
 					}
 				}
 				return Status.OK_STATUS;
diff --git a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/search/actions/OpenDeclarationsAction.java b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/search/actions/OpenDeclarationsAction.java
index b18f191f9fd..18665de3981 100644
--- a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/search/actions/OpenDeclarationsAction.java
+++ b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/search/actions/OpenDeclarationsAction.java
@@ -114,6 +114,9 @@ public class OpenDeclarationsAction extends SelectionParseAction {
 		}
 
 		public IStatus runOnAST(ILanguage lang, IASTTranslationUnit ast) throws CoreException {
+			if (ast == null) {
+				return Status.OK_STATUS;
+			}
 			int selectionStart = selNode.getOffset();
 			int selectionLength = selNode.getLength();
 				
diff --git a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/viewsupport/IndexUI.java b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/viewsupport/IndexUI.java
index 3aa0817419d..e4451ee0ed2 100644
--- a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/viewsupport/IndexUI.java
+++ b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/viewsupport/IndexUI.java
@@ -339,9 +339,11 @@ public class IndexUI {
 		final IASTName[] result= {null};
 		ASTProvider.getASTProvider().runOnAST(workingCopy, ASTProvider.WAIT_YES, null, new ASTRunnable() {
 			public IStatus runOnAST(ILanguage lang, IASTTranslationUnit ast) {
-				FindNameForSelectionVisitor finder= new FindNameForSelectionVisitor(ast.getFilePath(), selectionStart, selectionLength);
-				ast.accept(finder);
-				result[0]= finder.getSelectedName();
+				if (ast != null) {
+					FindNameForSelectionVisitor finder= new FindNameForSelectionVisitor(ast.getFilePath(), selectionStart, selectionLength);
+					ast.accept(finder);
+					result[0]= finder.getSelectedName();
+				}
 				return Status.OK_STATUS;
 			}
 		});