Index: menu.inc
===================================================================
--- menu.inc	(revision 11)
+++ menu.inc	(working copy)
@@ -396,7 +396,7 @@
     $path = substr($path, 0, strrpos($path, '/'));
   }
 
-  if (!isset($menu['callbacks'][$path])) {
+  if (empty($path) || !isset($menu['callbacks'][$path])) {
     return MENU_NOT_FOUND;
   }