I'm stumped. I've got some other ideas, but they're pretty random and might not fix the problem:

- Reflash the firmware (should be ver 1.68)
- Start deleting bunches of tracks and see if the problem goes away (probably very inefficient)
- Format (crappy thing here is you lose all playcount info for the DJ)

If you go with the delete or reformat option, make sure you've got the latest version of RMM running before you re-sync. IIRC, you want ver 2.96.

Good luck.