gmg dbupdate error

gistfile1.txt

sh-4.3$ ./bin/gmg dbupdate
/usr/lib/python2.7/dist-packages/gi/module.py:176: Warning: g_array_append_vals: assertion 'array' failed
  g_type = info.get_g_type()
/usr/lib/python2.7/dist-packages/gi/module.py:176: Warning: g_hash_table_lookup: assertion 'hash_table != NULL' failed
  g_type = info.get_g_type()
/usr/lib/python2.7/dist-packages/gi/module.py:176: Warning: g_hash_table_insert_internal: assertion 'hash_table != NULL' failed
  g_type = info.get_g_type()
-> Updating main mediagoblin tables:
   + Running migration 29, "migrate_data_foreign_keys"... Traceback (most recent call last):
  File "./bin/gmg", line 9, in <module>
    load_entry_point('mediagoblin==0.8.0', 'console_scripts', 'gmg')()
  File "/usr/local/mediagoblin/mediagoblin/mediagoblin/gmg_commands/__init__.py", line 142, in main_cli
    args.func(args)
  File "/usr/local/mediagoblin/mediagoblin/mediagoblin/gmg_commands/dbupdate.py", line 160, in dbupdate
    run_dbupdate(app_config, global_config)
  File "/usr/local/mediagoblin/mediagoblin/mediagoblin/gmg_commands/dbupdate.py", line 128, in run_dbupdate
    run_all_migrations(db, app_config, global_config)
  File "/usr/local/mediagoblin/mediagoblin/mediagoblin/gmg_commands/dbupdate.py", line 155, in run_all_migrations
    migration_manager.init_or_migrate()
  File "/usr/local/mediagoblin/mediagoblin/mediagoblin/db/migration_tools.py", line 288, in init_or_migrate
    migration_func(self.session)
  File "/usr/local/mediagoblin/mediagoblin/mediagoblin/db/migrations.py", line 1336, in migrate_data_foreign_keys
    obj_pk=activity_object.id,
AttributeError: 'NoneType' object has no attribute 'id'
sh-4.3$