Are you copy/pasting the code from the purchase into the redemption box, or are you trying to re-type it?

Sorry, I must ask =) If I had a nickel for every person I've helped over the years that was typing an 'O' instead of a '0' or an 'l' instead of an 'I', I'd be a rich man.

Anyway, if you are re-typing it, try ctrl-c and ctrl-v instead.

Good luck.