--- db.php	Mon Nov 03 21:15:59 2008
+++ db.php	Fri Mar 13 11:04:09 2009
@@ -80,7 +80,7 @@
     }
   }
 
-  function flush($flush) {
+  function flush($flush = NULL) {
     $flush = empty($flush) ? time() : $flush;
     $this->content = array();
     db_query("DELETE FROM {". $this->name ."} WHERE expire != %d AND expire < %d", CACHE_PERMANENT, $flush);