I just had the same issue with entering my Mtgox account number and not the exchange number, does anyone know if it will still go through, or if there is a way to fix it? I have emailed support a ton of times with no answers yet
This is my issue as well. They were like "no problem! Here's a mtgox code for that amount."
Then it turned out they gave me an expired code and haven't yet resolved the issue. Even though tech support admitted the code was invalid and escalated the case. I was told to contact the CEO of bitinstant, which I did, and have yet to see a response. Running out of patience.