Interestingly enough I went through their redeem process (which is sort of convoluted, with a password protected PDF), and was then told "This code has already been used. Each code may only be used once." when I tried to redeem the code they gave me...

So you might want to wait a bit until they sort out the bugs.

Me too, and I'm seeing a whole lot of other people with the same bug on twitter. Apparently AppleCare are saying codes will be reissued, so report the problem: http://www.macrumors.com/2012/07/25/apple-reissuing-os-x-mou...

edited to add: I've now had a response from apple after mailing support. We're getting new codes. NB they do mention doing this in response to a claim, so it appears you did need to contact Apple if you had a problem!

"Before I proceed I would like to point out that Apple is aware of the issue and are working hard to resolve it ASAP...If your claim is accepted, a valid replacement code will be sent to you by email. There will be no need to submit a new claim....Please let me know if you do not receive a replacement code within 24-48 hours, as I'll be happy to look into things further for you."

I am having the exact same issue. I'm hoping it's a minor issue with validation, but that seems like a weird message to get if that's the case?

edit: swapped "had" for "am having" as this is on-going

I have the new model. I don't see an option to select a macbook air when choosing the mac type. Guess I will be on call with apple..

I selected "MacBook" for my MB Air, and it worked, which is weird because I don't think they make plain MacBooks anymore.

They also ask for the address of the reseller, but I purchased mine from Amazon, so I just entered my address.

not working here either. the support forums are filled with complains :(