Thats an interesting fault. Suggest you try the following, start vlc or mplayer from the terminal, once the chapter stops the terminal may output some useful information.
As two different programs are both stopping at the same point, it sounds as though theres a problem with the optics or the dvd is dirty. If you see read errors on the terminal this will confirm this.
Clean the DVD with a micro fibre cloth, you can buy DVD lens cleaners or use a computer grade air duster to inject air into the dvd player. Hope that helps