Indygo: I'd just like to let everyone know that the game I sent Gede that the code failed because someone else claimed it. Yeah, that's my fault since I posted the code on Summer Sale thread for less then two minutes. I removed it from the post in that thread after I found out about this one so he's still looking for a copy of Garbriel Knight Remake. Sorry, I am a noob...
Yes. It's unfortunate. Still, you learned it the hard way and will know better next time. So there's a bright side to it too.
Alas, because of the way GOG implemented these codes (via email, rather than via orders & settings), you can't even say who redeemed it.