My LG GSA-4163B drive is having problems reading only select few of my DVDs. Here are the problems i’m encountering:
1 Multi-session DVD-ROM disc not reading later sessions.
Several DVD video discs, from retail, cause the drive to timeout when they are put in -These discs will not be recognised at all by the drive.
I’m using A105 firmware, and AnyDVD 5.9.4.1, on Windows XP Pro.
Ok, I tried the multi-session(dvd-rom) disc out again, and it’s reading it properly now (although it seems to be a recurring problem).
I’m still having the timeout problem with retail pressed DVD-Video discs, however. 
When you say that they will not be recognised by the drive, how are you trying to view those DVD video discs? With windows explorer?
The drives quits reading the disc after about a minute of it being inserted.
AnyDVD says nothing is inserted, same with explorer, VLC, etc.
This is very strange. Try doing something : reboot in safe mode and see if the discs in question can be read. Some DVD-Video discs show up as having no contents in explorer, but VLC should be able to play them. So try VLC in safe mode and see if the discs can be read.
Haven’t had a chance to reboot in safe mode yet, but I have found an error message in some form, using DVD Decrypter. The error message reads at the bottom of the main program screen “Device Not Ready (Logical Unit not ready, Cause not reportable)”
Nope, that error message doesn’t tell us anything new. It essentially means the same thing - could not read disc in drive. Try the safe mode thing I mentioned.