These comments are for learning purposes only. Copying copyrighted media is against the law in many countries.
How were those .vob files dumped from dvd?
Did you use something that used libdvdcss? If not the video's will be scrambled and unplayable. If you copied the .vob files from the dvd over to the card then the video's will be scrambled and unplayable.
If you have libdvdcss installed, an example would be
mplayer dvd://1 -dumpstream -dumpfile video.vob
Will dump title 1 on the dvd to video.vob
Do a search on how DVD's work and,
A .vob file from a dvd is usually mpeg2 video and ac3 audio.