Transfer purchases from iphone to MacBook Air?

Hi all,

When I go to File>Devices>Transfer Purchases from iPhone, I get this error message;

"Some of the purchased items on the iPhone "name of iphone" including "the Story," could not be transferred to your iTunes library because you are not authorized for them on this computer.

Would you like to authorize this computer for items purchased from the iTunes store?

If you do not authorize this computer, you will not be able to transfer items purchased on your i{hone back to your iTunes library.

When I select Authorize, I'm prompted to enter my Apple ID and Password.

Then it says, "This computer had previously been authorized, it has been re-authorized."

Then it gives me the same error message as before, with the prompt to "To authorize this computer for items purchased from the iTunes Store, choose Account>authorizations>Authorize This Computer.

WHen I do so, it says "This computer had previously been authorized, it has been re-authorized".

And around and around we go.

Please help - these are songs I purchased from iTunes on a prior computer. That computer is long gone but now the songs are only on my iPhone. Without transferring them to my iTunes, I can't sync without losing them all.