From Apple's FAQ for the shuffle:
"Can I use iTunes to view the songs on my iPod shuffle like I can with other iPods?
No. The iPod shuffle icon that displays in the iTunes Source list is actually a special playlist (like Party Shuffle).It lists which songs in the library are currently configured to be sent to iPod shuffle, but not what's currently on the unit. If you see a bullet by a song, it indicates that the song was not sent to iPod shuffle. See
"Some songs in your iTunes library aren't copied to your iPod" for reasons why songs were not sent to iPod shuffle."
Can you play songs from the shuffle?
srb