strange VOB files on dvd

hi all

I have a dvd that I own which is an instructional dvd. It contains a lecture and other portions. I have extracted the entire contents of the disk onto my computer to try and make it into 1 movie file. I am having a small issue though. I ahve gone through every single VOB file on the Video TS folder, and all of the dvd content doesn't seem to be there, yet when you play the DVD in a computer or DVD player, the lecutre and extra portions go for well over 2 hours.

I am thinking there is something encoding wise that is stopping me from ripping the entire disk off? or something hidden? has anyone ever come across this before?

thanks in advance.
an63lu5