diff --git a/apps/acls/managers.py b/apps/acls/managers.py
index 66991003d2..540c1ff3b2 100644
--- a/apps/acls/managers.py
+++ b/apps/acls/managers.py
@@ -259,16 +259,15 @@ class DefaultAccessEntryManager(models.Manager):
     """
     def get_holders_for(self, cls):
         cls = get_source_object(cls)
-        #if isinstance(cls, EncapsulatedObject):
-        #    cls = cls.source_object
-
         content_type = ContentType.objects.get_for_model(cls)
         holder_list = []
         for access_entry in self.model.objects.filter(content_type=content_type):
-            entry = ClassAccessHolder.encapsulate(access_entry.holder_object)
+            if access_entry.holder_object:
+                # Reference to a non existant content type object
+                entry = ClassAccessHolder.encapsulate(access_entry.holder_object)
 
-            if entry not in holder_list:
-                holder_list.append(entry)
+                if entry not in holder_list:
+                    holder_list.append(entry)
 
         return holder_list