Index: ckeditor/ckeditor.module
===================================================================
--- ckeditor/ckeditor.module	(revision 6971)
+++ ckeditor/ckeditor.module	(working copy)
@@ -1031,7 +1031,7 @@
         $css_files[] = $editor_path .'/contents.css' . $query_string;
         break;
     }
-    if ($conf['ckeditor_load_method'] == 'ckeditor_source.js') {
+    if (isset($conf['ckeditor_load_method']) && $conf['ckeditor_load_method'] == 'ckeditor_source.js') {
       foreach ($css_files as $k => $v) {
         $css_files[$k] = $v . '&t=' . time();
       }