problem playing DVD video using xine

[Bernard <bdebreil@teaser.fr>]

Hi to Everyone,

Out of 9 DVD that I bought, I can read only 4 using xine under Debian 
Lenny. With the 5 others, I get the following error message:

libdvdread: Encrypted DVD support unavailable

I suppose that I miss some codecs... in any case, I must admit that I am 
a newbee in DVD viewing, so I may miss something obvious.

On one of the five failing supports, the system proposed that I install

gstreamer0.10-plugins-bad

but this turned out to be impossible to install: the package is said to 
be available, but it says that it is defectuous and that it won't install.

What codecs or other utility should I install ?   In what repository 
would that be available ?

Thanks in advance for your help