Doesn't work? Are you using the wrong key? There's one to download and one to apply to your account.
Yeah I'm using the right one. The first one is the registration code, it worked. The second one is for PSN. I don't know what I'm doing wrong, but it sure isn't telling me :P
"Please enter your Prepaid Card number or Promotion Code"
"The Prepaid Card code you entered is incorrect or is no longer valid"