I checked both downloads and they are the same file. They also match the md5 posted on the first page, and I see previous posts from 2008 in this thread with the .exe (not .msi) in the image. So, I'm going to assume it's an .exe packaged msi distribution and that there was some kind of misunderstanding when the post was first put up as to the contents.
I installed it into a fresh copy of XP Pro under vmware, and it works. I'm now wondering if the problem is from the cd install stucking some stuff in the registry that the .exe doesn't address, screwing up the pointers to the game or something. Let me play with it some more and I'll get back to you. Something is causing this problem... And it's not the archetecture, since it runs fine from the cdrom install and there aren't any significant file differences between the two distributions.
Also, if you just want the .torrent for the iso image, check
http://dl.btjunkie.org/torrent/Nox-Westwood/4082e9b76d99654eb14ae646cee73f3e1ad1ed6fd36f/download.torrent. I doubt that link is going down any time soon.