can anyone help!!!!!!!!!!!!!!

i have a xvid movie file that im trying to convert to mpeg so i can back it up on to a dvd. movie is 2hrs 6mins long and has a ratio of 2.35-1. i have used tmpgenc before wit no probs but with this movie it goes black for t last fifteen minutes or so wen converting. i thought it was t file so converted wit ulead which it did fine all the way through but wouldnt keep t aspect ratio which i want to stay at 2.35-1.

anyone got any ideas?????? or failing that any other programs i could try that do the same thing but allow me to keep the aspect ratio as is

cheers