My kid bought a song from the iTunes store and can't sync it to his iPod. An error message comes up after syncing that says. "'(song)' wasn't uploaded to '(iPod)' because you don't have authorization on this computer". Anybody ever have this message come up?

He was on his own account and no dialog came up for me (the administrator) to authenticate. Just the error message with no clues on how to authorize.

Any ideas as to how to solve this? Could the song file be corrupt? Help!

Edit:
This occurred on an iMac, less than a year old, running a Snow Leopard.