Index: wp-admin/includes/plugin.php
===================================================================
--- wp-admin/includes/plugin.php	(revision 6317)
+++ wp-admin/includes/plugin.php	(working copy)
@@ -329,10 +329,10 @@
 }
 
 function get_plugin_page_hook( $plugin_page, $parent_page ) {
-	global $wp_filter;
+	global $wp_action;
 
 	$hook = get_plugin_page_hookname( $plugin_page, $parent_page );
-	if ( isset( $wp_filter[$hook] ))
+	if ( isset( $wp_action[$hook] ))
 		return $hook;
 	else
 		return null;
Index: wp-settings.php
===================================================================
--- wp-settings.php	(revision 6317)
+++ wp-settings.php	(working copy)
@@ -20,7 +20,7 @@
 
 wp_unregister_GLOBALS();
 
-unset( $wp_filter, $cache_lastcommentmodified, $cache_lastpostdate );
+unset( $wp_filter, $wp_action, $cache_lastcommentmodified, $cache_lastpostdate );
 
 if ( ! isset($blog_id) )
 	$blog_id = 1;