Not sure if the CE is still being supported at this time, but when I extract all the files in the .Zip file and click on NWLauncher in the created CE directory, I get to the startup menu, click multplayer then sign-in... I get an error about the individual player key not being the multiplayer key and to switch it in the "startup" menu??
I will attach a screen shot of the error:
Not sure if you already figured it out but I'll post this anyway, in case other people have the same issues:
The GOG NWN2 Version does not provide individual installations therefore the "nwn2cdkey.ini" is empty and the game cannot verify if you are a legal owner of this game.
In order to fix this problem, open up your gog online account page to figure out your NWN 2 game codes.
Then head over to your GOG GalaxyClient, select NWN2, click "More" -> "Other" -> "Multiplayer Key Changer"
This will open a small executable where you can enter the keys. Save and load and you'll be fine!