Even though this computer is already authorized for iTunes:
Following the directions on the warning message as seen in the screenshot:
I did authenticate this computer
Store | Authorize this computer
(which btw had already been authenticated in the past - so I don't know why it lost the auth..). But the error message continues to happen.
So then we are in a catch22. iTunes say I am already authorized but then turns around and says I am not. I have repeated this process to ensure it were not just temporary. Why the discrepancy here - and what to do to resolve?