Index: CKEditor/trunk/_source/plugins/indent/plugin.js
===================================================================
--- CKEditor/trunk/_source/plugins/indent/plugin.js	(revision 3391)
+++ CKEditor/trunk/_source/plugins/indent/plugin.js	(revision 3415)
@@ -236,5 +236,5 @@
 				nearestListBlock = range.getCommonAncestor();
 
-			while ( !( nearestListBlock.type == CKEDITOR.NODE_ELEMENT && 
+			while ( nearestListBlock && !( nearestListBlock.type == CKEDITOR.NODE_ELEMENT && 
 				listNodeNames[ nearestListBlock.getName() ] ) )
 				nearestListBlock = nearestListBlock.getParent();