The files in the zips are named 'language.dll.SW3.TrackIR' etc. make sure you delete the '.sw3.trackIR'. You will only see the whole name if you have the 'show known file types' option turned on.
After that just pop it in the main sim folder.
Other than that, it worked fine for me. It has been many years now since I installed this when some kind soul gave it to me here at the SoH. Sorry I forget who now. I've just transferred my installs from one PC to the next, so never re-installed it. I never had any issues that I remember.
Jamie