ITunes :: Won't Sync With Ipod Classic, Keeps Asking For Authorization

I have a brand new Macbook Air. I transfered my iTunes library from my old mac to the new one. However, some songs weren't on the old computer, they were only on the iPod classic. 

When I try to sync the iPod classic, it tells me 539 songs aren't on the new computer, should it sync? I say yes. Then it says that the computer is no longer authorized. I fill in the authorization with the correct userid and password (it comes prefilled with a very strange userid that I've never seen before.)  

It tries to sync, then I get the same message, that the computer is no longer authorized.  

I'm assuming there's a certificate or cookie some place that's out of wack -- can you tell me where it is and I can go delete it?  

PS. I was able to successfully sync my iPod Nano to the new computer without this issue at all. Then again, it didn't have any songs on it that weren't already on the new computer. I haven't tried syncing my iPod Mini to the new computer yet.

Info:
MacBook Air, Mac OS X (10.7.3)