You might be running into a bug in 2.0 beta 7, or you might have uploaded a bad MP3. Or perhaps there's an error in the database.

I suggest the following course of action:

Full downgrade to Emplode 1.03 and player 1.03, (no hijack) and do a couple of synchronizations to force it to rebuild the database. If the problems go away, leave it there until the next beta release.