DVD not playing on Acer

My post and response on Ubuntu Forums:

My son has an Acer Aspire One running Ubuntu, and has VLC installed.

As this machine doesn't have a DVD drive, he has an external LiteOn DVD multiformat drive.

He decided last night he wanted to watch Paul Blart Mall Cop (he's only 8!). The DVD went in the drive, the DVD showed on the desktop, and the message came up about "Open with VLC". Which we tried - and VLC closed.

I tried various other ways to get the disk to play - opening VLC and then choosing disk, double clicking on mounted icon on desktop, none would work.

I then installed Totem Movie Player to see if that would cope any better. It didn't.

The one thing I am wondering is about region - we have used the DVD drive in the past to play region free DVDs that I had burned myself, but this may be the first time we have tried one with region encoding.

Could that be it? If so, how do I determine in Ubuntu what region I have and how can I amend it if necessary?

Response:

I think, DVD is encrypted.

You need to add medibuntu's repository, and install libdvdcss2 package.

Add repository first using

sudo wget --output-document=/etc/apt/sources.list.d/medibuntu.list http://www.medibuntu.org/sources.list.d/$(lsb_release -cs).list && sudo apt-get --quiet update && sudo apt-get --yes --quiet --allow-unauthenticated install medibuntu-keyring && sudo apt-get --quiet update

Then

sudo apt-get install libdvdcss2