you're not supposed to delete any files
If you're using the original belini track and have the original belini folders, this should work as it is.
the question is : how are you running the game ? within the MOD or in another gp3 folder ?
Maybe your folder structure isn't right....
Anyway, if you know how to use the track editor, you're able to open the jam tree and compare that with the files you have or not.
You can also set the gp3 location to where the gp3.exe is located and check the jam index.
If you don't find it, send me an email with some other screenshots just to be sure, and maybe i can give more details on finding the problem.
my email is
dirkholemans@telenet.be in case you need it