--- a/includes/plugins.php	Fri May 29 16:38:51 2009 -0400
+++ b/includes/plugins.php	Fri May 29 20:22:30 2009 -0400
@@ -829,7 +829,7 @@
   function upgrade_plugin($filename, $plugin_list = null)
   {
     global $db, $session, $paths, $template, $plugins; // Common objects
-    global $lang;
+    global $lang, $cache;
     
     if ( !$plugin_list )
       $plugin_list = $this->get_plugin_list();