Help! Files are transferring but not showing up???

I just bought a 2 gig Fuze.  Trying to sync it with WMP 9.  Did a firmware update less than 2 hours ago.

I build the playlist in WMP and tell it to sync.  It goes through all of the motions, and the device shows as having the files on board, but when I try to play them my Fuze tells me there are no songs loaded.

Everything else seems to work as intended, but the music files I’ve transferred are just not playable.

Help?

problem solved.  updated WMP to v. 11.  rebooted, plugged back in and tried again.

worked this time.