I had the same problem:
- linux user
- using picard
- ogg files
- dolphin-generated generated OGG files played fine, though no album art (for those unaware, the dolphin file browser will generated you several different formats if you browse to audiocd:/ in kubuntu 9.10)
- those same OGG files run through musicbrainz would cause the database refresh to freeze
I upgraded the firmware to .31 (V1 for me) and now these songs will sync, album art at all.