Downloaded, burn but has broken sound? What?

I downloaded two recently released movies that were in an .iso format. I burnt them to dvd and tried to play it on my computer. The video was consistent but the sound was broken through out the entire movie. I am not sure why this is. I thought it might be purposeful but a lot of people have downloaded it so I wasn't sure if it was an isolated issue. Does anyone know if I can some how recover the full sound of these files? Also, I burnt them using nero. Any help will be appreciated.