Index: django/db/models/manipulators.py
===================================================================
--- django/db/models/manipulators.py	(revision 3522)
+++ django/db/models/manipulators.py	(working copy)
@@ -138,7 +138,9 @@
             child_follow = self.follow.get(related.name, None)
 
             if child_follow:
-                obj_list = expanded_data[related.var_name].items()
+                # expanded_data[related.var_name] won't exist if no related 
+                # objects were displayed on the form.
+                obj_list = expanded_data.get(related.var_name, {}).items()
                 if not obj_list:
                     continue