Index: includes/menu.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/menu.inc,v
retrieving revision 1.79.2.1
diff -u -p -r1.79.2.1 menu.inc
--- includes/menu.inc	5 Jun 2005 09:47:51 -0000	1.79.2.1
+++ includes/menu.inc	28 Nov 2005 02:02:51 -0000
@@ -970,10 +970,12 @@ function _menu_find_parents(&$items) {
     if (!isset($item['pid'])) {
       // Parent's location has not been customized, so figure it out using the path.
       $parent = $item['path'];
-      do {
-        $parent = substr($parent, 0, strrpos($parent, '/'));
+      if ($parent) {
+        do {
+          $parent = substr($parent, 0, strrpos($parent, '/'));
+        }
+        while ($parent && !array_key_exists($parent, $_menu['path index']));
       }
-      while ($parent && !array_key_exists($parent, $_menu['path index']));
 
       $pid = $parent ? $_menu['path index'][$parent] : 1;
       $_menu['items'][$mid]['pid'] = $pid;