I recently preordered The Witcher 3 here on GOG and yet for some reason I haven't gotten the free copy of Neverwinter Nights.
Sure, I might have decided to preorder it when its just a few days away from release, but surely that offer is still valid, right?
I'm just curious.

Code and link to redeeming site should be in your mailbox - purchase confirmation from gog.com.

I never got the code in any confirmation email- just the confirmation that my pre-order was good ... saem with the expansion. All the other free games popped up in my game library except the for the Neverwinter Nights. I went back to the pre-order description and it is plain as day that is suppose to be included in the pre-order. I am not too worried if it doesn't happen, but I would like to see if others did receive the game. I pre-ordered like 3 months ago.

The key was in my mailbox. Just had to click a link in the Witcher 3 purchase confirmation email to redeem the NN key.

Installed and played a while with no issues.

I just purchased about a month ago. April 20 to be precise.

Whoops, I forgot to check that. XD
https://www.youtube.com/watch?v=kp1f1ig79_0

For some reason whenever I try to redeem my code, I get a message that says "The redirect URI provided does not match registered URI(s)" Anybody know what is happening here?

I pre-ordered on june 5th, 2014
just now tried to redeem Neverwinter, and I get an error 'Code Invalid'
:(

Contact support, they will sort you out. It may take a few days but they are very helpful.