Index: includes/menu.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/menu.inc,v
retrieving revision 1.291
diff -u -p -r1.291 menu.inc
--- includes/menu.inc	20 Sep 2008 20:22:23 -0000	1.291
+++ includes/menu.inc	22 Sep 2008 00:43:00 -0000
@@ -2340,10 +2340,11 @@ function _menu_router_build($callbacks) 
   }
   array_multisort($sort, SORT_NUMERIC, $menu);
 
-  if ($menu) {
-    // Delete the existing router since we have some data to replace it.
-    db_query('DELETE FROM {menu_router}');
+  if (!$menu) {
+    return array();
   }
+  // Delete the existing router since we have some data to replace it.
+  db_query('DELETE FROM {menu_router}');
   // Apply inheritance rules.
   foreach ($menu as $path => $v) {
     $item = &$menu[$path];