i noticed that many people are complaining about not playing mkv files on ubuntu, including myself.....

so i started to compile VLC and noticed that when it's setting the matroska driver it searches for something else...

Before you can play MKV files you need to do the following: In Konsole type...

1- sudo apt-get install libebml-dev

2- sudo apt-get install libmatroska-dev

3- sudo apt-get install libmp4v2-0 libmp4v2-dev

After Installing these 3 files you will need to compile VLC, remember to get all VLC dependencys.. try this

4- sudo apt-get install libdvdcss2 libdvdcss2-dev libdvdplay0 libdvdplay0-dev libdvdnav-dev libdvdnav4 libdvdread3-dev libdvdread3 libogg-dev libogg0 libvorbis-dev libvorbis0a liba52-0.7.4-dev liba52-0.7.4 libmad0-dev libmad0

5- Go to http://www.videolan.org/vlc/download-sources.html
and download the latest vlc source code, i have 0.8.4a and get ready to compile it...

6- Extract the file typing "tar -zxvf vlc-XXXX.tar.gz" and go in the extraxted directory,

7- Type "sudo ./configure --enable-mkv" (this might take a while)

8- Type "sudo make" (this also might take a while)

9-Type "sudo make install"

if everything went well, try "vlc --list |grep mkv" it should display a line with "mkv Matroska stream demuxer"

i'm assuming that you have installed the packages to compile... if not, try
"sudo apt-get install build-essential autoconf automake1.9"

enjoy...