I can vaguely remember, that I tried to install Nexus using the key he provided. The installer didn't accept it, naturally, so I tried looking for the most trivial user-made errors I could think of, like mixing up 1 with I or 0 with O. Changing the last 1 to i did the trick and the installation continued, so that's why I suggested the change to him.
As for your problem: if your own Nexus key doesn't work and the one from that particular thread did neither, then it got to be some other problem related to Linux. It sounds like it fails on game startup... didn't you have to enter it during installation? I'm not really familiar with Wine or the typical game installation process there, so please indulge me.
Well, the key usually gets stored in the Windows registry and I don't see why the game authenticating a legit key should fail specifically under Linux. I'd guess, it simply can't find the key in the registry (which I suppose Wine has to emulate somehow) and thus can't authenticate it, of course.
Which distro do you use?