Error message and poster not saved

Using postgresql, in the "Add a new movie" dialog, I successfuly pull information from imdb.
But when I hit "Add movie" an error message pops up:

insert or update on table "movies" violates foreign key constraint "movies_poster_md5_fkey"
DETAIL: Key (poster_md5)=(c3acc3c00b80dc2f9062f539c6991486) is not present in table "posters".

When I close that popup and then hit "Add movie" again, the movie is added but without its poster. The command line then shows:

2011-02-05T10:35:47: W: Griffith(add:677): cannot read temporary file: /tmp/poster_HrpeTq.jpg

Haven't looked at the code yet. Given that the second click doesn't have a problem with the primary key, probably needs a flush "inbetween" so that the primary key becomes available. The poster not being found I guess is just because the file gets deleted during the first attempt, probably assumed it was already put in the database.

There is something else also pointing to a timing/commit issue - maybe autocommit was turned off recently?
When a field value is too long - for example "Studio" has more than 128 characters, I get an error message on the command line (clicking "Add movie" seemingly does nothing)

2011-02-05T10:58:19: E: Griffith(add:824): Unexpected problem: (DataError) value too long for type character varying(128)

In such a case I used to be able to just edit that field manually, and try again. In the current version though, a second attempt brings

Traceback (most recent call last):
  File "/usr/bin/griffith", line 334, in add_movie_db
    add.add_movie_db(self, 0)
  File "/usr/share/griffith/lib/add.py", line 645, in add_movie_db
    if session.query(db.Movie).filter_by(o_title=details['o_title']).count() > 0:
[...]
  File "/usr/lib/python2.6/dist-packages/sqlalchemy/orm/session.py", line 233, in _assert_is_active
    "The transaction is inactive due to a rollback in a "
sqlalchemy.exc.InvalidRequestError: The transaction is inactive due to a rollback in a subtransaction. Issue rollback() to cancel the transaction.

http://www.sqlalchemy.org/trac/wiki/FAQ#Thetransactionisinactiveduetoarollbackinasubtransaction