Thank you for your post.
I don't know if the corrupted files can be fixed.
There are too many factors that cause file corruption. Some of these include power surges when writing to the file, bad sector on disk, memory problems, etc.
I would like to see a good backup file and your most recent backup that is not working. I have sent you a private message (top of this page - right side - X Messages) with instructions where to send those files.
In the future, please post your Bento questions to the Bento forum at http://forums.bento.com