Sorry to be slow to respond. I don't hang out here much anymore...busy, busy.
Well, my next guess is you might have a corrupted database.
Try creating a new database, and plopping your movie into that. If it works, you might have a bad sector on your hard drive. You can run error checking against the drive to see if that fixes it, or you can install a firebird server and use a repair tool for the database. From PVD, optimise MIGHT work, but doubtful...and it's likely to cause data loss as well. Exporting the title and imdb urls into a file and importing them into the new database might be a good option...just run a mass update on all records.
Yah, my collection is a bit out of hand. Database is just under 2GB. Almost 9k movies, 130k people. About 25% of people have a least one photo. No screen shots. Been pruning the worst of the worst to make space, but it's a slow process.