Not necessarily, in total I must have input my code a dozen times or more since this morning, and I only got the one EMail. The way it went down for me was:
Attempt 1: There was an error, please try again later.
Attempt 2: There was a problem with your code, please make sure you entered it correctly.
Every subsequent attempt: Same as Attempt 1.
I assume that my code went through on the first try, but I got the error message. The second time I tried it was basically telling me that my code had already been redeemed. As to why the remaining attempts yielded the first response... well, I dunno. I am thinking that once you get the second error, your code has been redeemed and you should just wait for the EMail. I am sure the hamster running the EMail server is working his tail off trying to send out all the EMails, so give him a minute to catch his breath. This is all conjecture on my part of course, but I hope it adds to the overall collective of information and we can nail down the situation.