(slightly OT) MPlayer can't open VMG info

Hi, I have SuSE 8.0 on an athlon 1600xp. I have installed MPlayer 0.90rc4. It works with video files, but when I try to watch a DVD, it refuses and the warning issued is "can't open VMG info". This happens both as User and as Root. Ther should be no hw problems since my DVD works OK with winXXX. I have read the documentation, but I got no help. Any Idea ? TNX, Riccardo,Italy