The track is not faulty. I can use this track from plodekk's 1991 trackpack, using GPxTrack (i.e. not using TSM).
The problem is, you have to remember that you're taking the track from a TSM trackpack. TSM has the ability to rename both the wad file itself, AND the files within the wad file (which is important). If you want to use the track outside of TSM, it is up to you to make sure the wad filename is correct, because TSM is not there to fix it for you. I will explain how to make a TSM track work, without TSM:
Every track wad file contains some files which all have the same filename. Open up any track wad file and you will find a folder called "maps". Inside "maps" are two folders, one called "resources" and one other. This other folder has some name. If you open this folder, you will see lots of other files also with the same name.
This name is called the "
Prefix". The important thing you must know if you want to use a track
without using TSM is that the
wad filename must match the Prefix.
So looking at this Mexico 1991 track, for example, it was quite easy to find why you are having a problem. Go to your GP4 folder\Tracks\1991 Mexico City\1991 and you will find these 4 files:
Default.tmd
mexico1991.wad
S1CT09.DATsettings.ini
Firstly, you must take the dat and wad files and put them somewhere else, on their own. Otherwise the settings.ini (a file that TSM uses) will interfere.
Now, open mexico1991.wad and you will find the "maps" folder I mentioned above. Inside this is the "resources" folder, and another folder, called "
nurburgring2001". This is the Prefix for this wad. So we can easily see why there is a problem; the filename of the wad - "mexico1991" - does not match the Prefix - "nurburgring2001".
So to fix this, simply rename mexico1991.wad to nurburgring2001.wad.
(I realise this contradicts what I said earlier about never renaming the .wad file, but I wasn't clear that you were using a track you got from a TSM trackpack).
=====================================================
Intel NUC 8i3, 8GB RAM, MS Sidewinder Wheel