I suspect Totem is missing some Gstreamer codecs, maybe the so called "Ugly and Bad" plugins, see here under "Codecs" about the middle of the page;http://projects.gnome.org/totem/
I looked in the repo and there is a cr*p load of Gstreamer plugins there that aren't installed, but none are described as being needed for DVD. Siamer did include the mp3 plugin with his re-master but not the mpeg2 plugin. Maybe that is the problem???
If you check out Gstreamer they admit that the "ugly" plugin could cause problems for distros and by extension individuals due to license violations. The sound codecs are the worst, thanks to the RIAA & other boneheads.