--- activity.module	Mon Nov 23 02:05:44 2009
+++ activity.module	Thu Nov 26 12:08:16 2009
@@ -178,6 +178,11 @@
     'file' => 'activity.admin.inc',
     'type' => MENU_NORMAL_ITEM,
   );
+  $items['admin/settings/activity/manage'] = array(
+    'title' => 'Manage',
+    'type' => MENU_DEFAULT_LOCAL_TASK,
+    'weight' => -10,
+  );
   $items['admin/build/activity/configure/%actions'] = array(
     'title' => 'Edit',
     'description' => 'Modify how your activity messages will look',
@@ -569,7 +574,7 @@
   // still needs to happen and does
   // @see activity_record
   foreach ($modules as $module) {
-    $grants = array_merge_recursive($grants, module_invoke($module, 'activity_grants', $record, $object, $type));
+    $grants = is_array($module_grants = module_invoke($module, 'activity_grants', $record, $object, $type)) ? array_merge_recursive($grants, $module_grants) : $grants;
   }
 
   return $grants;