Why does the sound go out of sync when I burn a DVD?

I have burned a dvd off three times and the sound keeps going out of sync. It'll go out for a few seconds then it'll get into sync again..... I've tried changing the burning speed, but that's done nothing. My laptop is only a few weeks old (it's a Toshiba Satellite), so it's not the burner. I use DVD Flick to burn off the movie. Anyone got any ideas? Thank you.