Okay. Im not sure what you've tried, but here goes.
I know you have winzip, so i wont tell you to get it.
1. Go to
www.warsplace.com and click the PODINI2.zip, right under where it says in very large text, "Need the patch? ..." (etc). It's not hard to find.
2. Open the zip file and extract ALL CONTENTS to your Monster Truck Madness 2 directory. (The default is: c:\program files\microsoft games\monster truck madness 2 - VERIFY WHERE MTM2 IS LOCATED, otherwise you wont know where to extract things.)
3. Go download the track or truck you wanted to use. It will be in a zip file.
4. Open the zip file from where you saved it. (Be sure to note the name of the .POD file that resides in it. You will need this info later.)
5. Extract all the contents to the MTM2 directory. It should be the same directory that you downloaded PODINI to.
6. Now, navigate to your MTM2 directory. (From my computer or something.)
7. Once you get there, you should see a bunch of pod files along with a few EXE's. In the directory there should be PODINI2.EXE. Open it.
8. A list will come up, listing all of the trucks/tracks that are installed in the game. The one(s) you downloaded will be at the very bottom of the list.
9. In the very left column of the list, there are the words YES or NO. This indicates if a pod is enabled or not. (Yes next to the ones that are, NO to the ones that arent.) --- Your's will have NO next to it, because they are not enabled yet.
10. To enable them and have them used in game, simply DOUBLE CLICK on the YES/NO of your pod. It should turn to YES, indicating that it is enabled.
11. Hit OK.
12. Fire up your MTM2 and your new track/truck should be in the list.
13 Have fun!
Now, i'm not sure if you've done all this or not, but even if you have, try this again to double check.
I hope i helped and that this solves your problem, and if not, then i'm sorry, but i don't know whats wrong!
Good luck, my friend.