Ok - I have a Thinkpad 600 with 192mb ram, a 300mhz processor, and a DVD drive (Heh, yeah, I know - The laptop had XP originally, and the DVDs stuttered a little on it, but it was tollerable). Anyway, I was going to run Xine to check it out in Linux - and it'll play the FBI warning crap, but when it gets to the menu it gives me an error about either permissions or something else (Sorry, I'm currently rebuilding the kernel and I want to finish that before I do anything else). I checked the permissions, and they should be fine. The DVDs I tried to play in it are fine as well. I can't remember the model of the DVD drive, but it's an internal one designed for the Thinkpads (I could look it up if you need me to).

Slackware comes with a couple of thing missing to watching DVD through xine
libdvdccs to see encrypted DVDs and permissions on /dev/dvd and where it actually points to.(usually /devhdc).
Those devices are, by default, included into disk group.
So, if not already done, install libdvdcss and include yourself as normal user into the disk group.
In order to make sure this is a permission problem, log in as root and try watching a DVD through xine.
Hope this helps

lol, that sucks. Thanks though, I should be done building the modules any time now and I'll try it out.

Ok, it worked. Thanks.