If he can't mount the drive I doubt it's user-land related. All you need to mount a disk is a kernel with the relevant stuff enabled and the mount command, nothing else.
This sounds to me rather like faulty disks and/or drive, or maybe your drive is not able to read a given type of disk for any reason.
Let's check the trivial stuff, not even Einstein was immune to silly errors. First, the drive can read dvd disks, right? Try this command right after booting:
sudo dmesg | grep -i dvd
And post here the output.
If dvd's don't work, try a regular cdrom and see if you can mount it. I've seen dvd drives which after some years of operation couldn't read dvd's any longer, but they had no problem with cdrom', which will be indicative that the lens used to read dvd's has died and cdroms are handled by another independent lens. That wouldn't fix anything, but you would then be sure that the problem is in the hardware.
I assume you've tested a different distro (that's what livecds are for) and that you have the same problem. If not, please, try it as well.