HELP ASAP!

I have TNT2 and when I run Open GL on tribes, it looks great except for THE LINES GOING THROUGH THE LANDSCAPE and THE EXTREMELY TERRIBLE LAG I GET JUST BY PLAYING OFF LINE!!! Something is wrong and I dont know what it is, please help me because i really really want to get open gl to work right so I can get Tribes 2!!! HELP, IM ON MY KNEES!!!

yeah i get the same s*!t on Q3