I tried importing everything but edit from the 20120922 dump and the import failed because of some cover art fk issues. I dumped and reimported everything including edit and it worked fine.

Error message: insert or update on table "cover_art" violates foreign key constraint "cover_art_fk_edit".
Log: http://pastebin.com/S0iD8k8j
Nikki dug out the relevant code: https://github.com/metabrainz/musicbrainz-server/blob/master/admin/sql/caa/CreateFKConstraints.sql