To recreate:
 - Check out gsoc-2009
 - Change the demo's template from "classic" to "deval" (see below)
 - Run the demo
 - Try to create a new bug

Adding the 'patches' property to the schema by hand makes things happy, though.

Changing demo's template:
--- demo.py	(revision 4385)
+++ demo.py	(working copy)
@@ -147,7 +147,7 @@
     nuke = args and args[0] == 'nuke'
     if not os.path.exists(home) or nuke:
         backend = 'anydbm'
-        template = 'classic'
+        template = 'devel'
         for opt, arg in opts:
             if opt == '-h':
                 usage()