=== modified file 'includes/menu.inc'
--- includes/menu.inc 2010-10-04 18:17:17 +0000
+++ includes/menu.inc 2010-10-05 06:38:25 +0000
@@ -2334,7 +2334,9 @@ function menu_link_get_preferred($path =
     $query->fields('ml');
     // Weight must be taken from {menu_links}, not {menu_router}.
     $query->fields('m', array_diff(drupal_schema_fields_sql('menu_router'), array('weight')));
-    $query->condition('ml.menu_name', $menu_names, 'IN');
+    if (!empty($menu_names)) {
+      $query->condition('ml.menu_name', $menu_names, 'IN');
+    }
     $query->condition('ml.link_path', $path_candidates, 'IN');
 
     // Sort candidates by link path and menu name.