the video you converted is muxed which means the audio and video are on the same track, quicktime or iTune can not deal with this kind of videos(they will drop the sound), you will need another 3rd party tool to help you, take a look at http://forums.afterdawn.com/thread_view.cfm/297023 this step by step guide convert DVDs and all kinds of videos like avi, mpeg etc to ipod using cucusoft.
or you can just buy DVDFab Platinum and click on iPod to convert your DVDs to mp4s and then import the movie to iTunes. very simple very easy! I love it!
