Your trouble is simply to solve!
Todays distro like Mandrake 10.1 SuSe 9.2 and maybe other that I haven't tried do to legal and copyright issues don't support anymore DVD viewing.
It's depend to the lack of a library (libdvdcss) that the above distros don't include necessary to unencrypt DVD contents.
Download and install the library from the bottom link.
It's for Fedora fc1 but should work for mandrake also.
On my mandrake 10.1 I use libdvdcss from RedHat 9 but it works great and I can view all DVD's I want.
Let me know!
walker
http://dag.wieers.com/packages/libdv...1.dag.i386.rpm