I am confused.
What changed a playlist (.hst) file or a song file?
In case you forgot all of the working files (database, playlists, songbook, etc. all moved with 3.319. They were reloacted to
C:\Documents and Settings\%USER%\Local Settings\MTU\Hoster
You also did (previous posts) a Merge on your database which may have changed some of the BookID's. If you are using a playlist that was created before the Merge then it may have the old BookID.