intermittent dvd playback

Hello Debian multimedia users,

Even though I have the package libdvdcss2 installed as well as the
libdvdread and libdvdnav packages from debian main (as well as all the
gstreamer plugins), some DVD's fail to playback correctly. Totem gives
a popup error saying it can't read from source and vlc simply freezes
and after a few seconds it stops playback altogether.

I have tested the DVD's on my friend's laptop running Windows Vista
and playback was flawless. I also noticed that if I let some
considerable time pass, the dvd played fine, well at least the parts
that were previously freezing/stopping. This made me suspect my
hardware, but some dvd's don't have problems.

Is there any known issue?

Andres