DVD drive not reading dvd's

Question

I have done the regionset thing, but the drive doesnt find a dvd when I do. I have added the css file I have tried manually mounting the drive and get

Failed to mount '/dev/sr0' to '/media/apt/' E: Unable to locate any package files, perhaps this is not a Debian Disc or the wrong architecture?

I have a brand new hp probook 4430s. I wiped windows and installed ubuntu. Some dvd's have played, and some havent and there seems no rhyme or reason to play or not. (I still have a list of dvd_css's in the .dvdcss file.)

I have read pages and pages of helps trying to find the answer and as yet no answer has fixed my problem

    *-cdrom
         description: DVD-RAM writer
         product: DVD RW AD-7711H
         vendor: hp
         physical id: 0.0.0
         bus info: scsi@1:0.0.0
         logical name: /dev/cdrom2
         logical name: /dev/cdrw2
         logical name: /dev/dvd2
         logical name: /dev/dvdrw2
         logical name: /dev/sr0
         version: 1.82
         capabilities: removable audio cd-r cd-rw dvd dvd-r dvd-ram
         configuration: ansiversion=5 status=nodisc

There was a disk (RV with robin williams) in the drive at the time. Using VLC, I set it to open /dev/dvd2 (as thats the address of the drive it seems) instead of the default /dev/dvd and got this error:

Playback failure:
DVDRead could not open the disc "/dev/dvd2".
Your input can't be opened:
VLC is unable to open the MRL 'dvd:///dev/dvd2'. Check the log for details.

Answer 1

Examine the offending disk to insure it has no deep scratches that would interfere with the lasers ability to read it. Once you are certain you have a good disk:

Open VLC, hold the CTRL key and tap D

This setting works fine for me. /dev/sr0 also works for me.