Okay, a couple of things to check:
If you just did a fresh install of TRON 2.0 on Vista or Windows 7, make sure you are running the game in Administrator mode. Otherwise, the game will not create certain files the mod needs to install. You will get a "TRON 2.0 has not been run before" error when attempting to install the mod.
To prevent this: Right click the TRON 2.0 shortcut icon, choose Properties, go to the Compatibility tab, and put a checkmark in the "Run this program as an administrator" box. Then run the game at least once.
See if that works. If not, check for these files in your Tron 2.0 folder. (The folder is probably located at "C:\Program Files\Buena Vista Interactive\Tron 2.0".)
A text file in the "Profiles" folder (probably named Player.txt)
All of these files must be present or the mod will not install. These files are generated by the game when it runs for the first time, provided it has the necessary privileges in Vista or 7.