I've searched around for an answer to this question - I know its not a unique problem, but it appears that its been solved behind the scenes by tech support for all who have come before me. Trouble is, I can't seem to actually get any tech support. So here I am.
I bought NWN Platinum used through Amazon. 2 of the CD keys provided by the previous owner worked. The one for Hordes of the Underdark did not. Desperate, I got a CD key for it from the internet. Inappropriate, I know, but I legally bought the game and wanted to play it.
Well, now I want to play in LAN with my wife. She also owns a legal copy aquired through Amazon. Unfortunately, when I go to Create a New Account for multiplayer, I get the "You are BANNED" message every time. I assume it is because of the false CD key I had to use to get it installed to begin with.
I need help. I paid for this game, I want to play it. Tech support that can't be reached is not tech support.