Toast Help? Not burning audio

I am having trouble burning dvd's. I copied my p90x dvds to make a copy for my girlfriend.

when i try to burn them using toast it burns the DVD but it has no audio. The video plays fine on the computer so i know the file works.

However if i put the dvd in the computer it still has no audio.

any solutions?

Does it play fine in Quicktime or is it VLC you are playing the original files in