Messed up audio when converted to Mpeg4

Hey, thanks if you help. Everytime I try to convert a movie I have to Mpeg4, the audio is off. I have the actual DVD, I wanna convert it to Mpeg4 to put it on my Zune(like an iPod), but the audio is never correctly synched with the video. Im using dvdXsoft to rip it straight off the DVD to Mpeg4. Ive tried ripping it to WMV too, but the audio was still off. Any way I can fix this without completely ripping/converting again? Thanks