--- og-a.inc	2012-11-07 15:47:05.000000000 -0500
+++ og.inc	2012-11-07 15:44:21.000000000 -0500
@@ -32,7 +32,7 @@
         $keys[] = $gid;
       }
     }
-    elseif ($object_type === 'comment' && !empty($object['nid']) && ($node = node_load($object->['nid'])) && !empty($node->og_groups)) {
+    elseif ($object_type === 'comment' && !empty($object->nid) && ($node = node_load($object->nid)) && !empty($node->og_groups)) {
       foreach ($node->og_groups as $gid) {
         $keys[] = $gid;
       }