Hmmm… a couple of thoughts. I assume you have libdvdcss2 (because I see this is a VOB in a video_ts directory, suggesting you were able to decrypt the DVD and backup to your hard drive).
I also note “ac3”. … Do you have a 64-bit openSUSE and a 64-bit vlc installed? If so, I have been told by a user on IRC freenode #suse that 64-bit Linux vlc has a bug that it gives no audio with ac3 codec. And I note this is ac3 codec.
Try playing the .vob with smplayer or with xine-ui.