is this an old update or when that just came out? I am not on my mac right now, so i can check in an hour when i get back from class. I have never been asked for the cd key when updating before. You might be able to e-mail apple to get your key, I have done this before to get my quicktime pro key, don't know if that works the same for aperture or not, probably depends on if you registered it or not.