Okay... The files should mostly be in WINRAR. The tracks you have in your game were obviously Zip files which would have zipped straight in there. If you have downloaded any DTR1 or DTR-0SC files, they will crash if you have put them into your DTR2 game.
1- Open up your game data folder under c/:/Games/Infogrames/Dirt Track Racing 2 and look for the Data folder. Open it and you should see [Tracks{ right in there with several other folders incl [Cars] and[skins]. If you are putting in some tracks, then open the [Tracks] folder. Put down on taskbar.
2-Open one of the tracks with WINRAR and open to the yellow folder which states the tracks name.. eg Rotten Speedway.
3- Do a drag and drop onto the [Tracks] folder sat there waiting on your taskbar.
All done... As long as you have as I have said, put the right game track etc into your game. And don't go putting skins in tracks for instance, either. If there are no folders created for the various items as above, then you must create one for each but it sounds like that's all good.
NB - There should be no WINRAR or Zipped folders inside any of the game folders. Your game will never go.
That's what's happening, but until we get some error readings from you, we can only think that's the problem...Hope this helps.
Good luck --- Paul D kiwi