Index: contrib/comments/models.py
===================================================================
--- contrib/comments/models.py	(revision 6917)
+++ contrib/comments/models.py	(working copy)
@@ -257,7 +257,7 @@
         if int(comment.user_id) == int(user.id):
             return # A user can't flag his own comment. Fail silently.
         try:
-            f = self.objects.get(user__pk=user.id, comment__pk=comment.id)
+            f = self.get(user__pk=user.id, comment__pk=comment.id)
         except self.model.DoesNotExist:
             from django.core.mail import mail_managers
             f = self.model(None, user.id, comment.id, None)