Index: spritemenu.module
===================================================================
--- spritemenu.module	(revision 1238)
+++ spritemenu.module	(working copy)
@@ -292,7 +292,7 @@
 
 function spritemenu_menu_link_alter(&$item, $menu) {
   $spritemenu = db_fetch_object(db_query("SELECT * FROM {spritemenu} WHERE mid = %d", $item['mlid']));
-  $match = preg_match("/spritemenu-([0-9]*)(\W|$)/", $item['options']['attributes']['class']);
+  $match = isset($item['options']['attributes']['class']) && preg_match("/spritemenu-([0-9]*)(\W|$)/", $item['options']['attributes']['class']);
   if ($spritemenu) {
     if ($match) {
       $class = preg_replace("/spritemenu-([0-9]*)/", 'spritemenu-' . $item['mlid'], $item['options']['attributes']['class']);
@@ -306,7 +306,7 @@
     $class = preg_replace("/spritemenu-([0-9]*)/", '', $item['options']['attributes']['class']);
   }
 
-  if (!is_null($class)) {
+  if (isset($class)) {
     if ($class == '' || $class == ' ') {
       unset($item['options']['attributes']['class']);
     }