Problem Joining Mpeg?

got the 3cd version of the hulk,but i wanted to join it together so i can put it on a dvd-r joined it with tmpge but now the sound is out of sync,so how can i join them without this happening,anyone help or surgest a good free prgrame that wil do this and not make it out of sync ?

Can you not put multiple files on DVD, just put them on order on the dvd, the lapse will be very small between files, probably the same as if you join them.