Problem with iTunes 8.1.1 . . .

[WHiiP]

After updating to iTunes 8.1.1 I have been thrown into circular "hell". I try to sync my iPhone and get a box saying my computer is NOT authorized. I try to authorize it from that dialogue box and get a box telling me that my computer is already authorized.

I then deauthorized it and reauthorized it. Get the same circular problem.

I then de-authorized it again. Then I let the dialogue box guide me to re-authorizing. Still get the circular problem.

Help.

Please.