Exactly what happened to me. I was so bummed this morning. I hated missing out on this one. I wonder if it is an iPad issue instead of a code issue considering it happened with us three on more than one app. Hmmm. Thanks for the response. It is nice to know it is not just happening to me.
iTunes has been jacked up for me as well. When I enter a promo code, it always prompts for a password. Then, if the code has been redeemed, instead of getting the "this code has been redeemed" message that I used to get, the Redeem Code screen goes blank, without any sort of acknowledgement. I have to close and then reopen the app store to try another code. If the code is good, it starts to download. So, the only way to know if the code really worked is if the app downloads to my device. It's weird, but as long as you know how it works, you can still redeem codes. The bottom line is that if the redeem page of iTunes goes blank, then the code is no good.