Hi, I've had this problem now with my LG GSA-4163B drive for some time. What happens is it will not read only certain commercial dvds. It will read everything else!
I'm using Windows XP Pro, AnyDVD (126.96.36.199) on a Pentium 4 system, with 512MB RAM.
I've tried swapping IDE cables, booting into Safe Mode.
Edit: I'm also using firmware A105