Thanks for the tip! It compiled now.
And i actually got to play one of the mkv movies - the dvd one.
However! The quality of this video was not impressive compared to the quality i get in windows. The linux picture is somewhat... blocky

Not big blocks but you can see the border and edges of stuff on the scene being very blocky. Also it crashed once when i searched fast through the movie, havent played much with it yet so dont know if its a persistent error.
And i still got the problem with the CPU usage going up to 100% whenever i play an mkv file in VLC.
Which leads me to the next problem: the other movie plays now, but it doesnt seem like the codec stand a chance to decode all the data. I get very low frame rate when i play the movie (like 1 frame every 4-5 seconds in VERY bad quality). I suspect this problem might have something to do with the 100% CPU usage. Something we forgot to optimize? Some setting that needs to be changed?
I know i dont have a super super strong CPU but a barton 2500 should still be able to run a HD movie. At least i think so
And the last thing. I don't have the original look and feel of the VLC player. Do i simply just install the vxwidget skin and all is back to normal?
Anyways! Thank you for helping me out here
EDIT:
Actually come to think of it, the quality is the same as the MPlayer is able to produce (except MPlayer also makes some green 'smudge' at the left area of the screen). The quality might be a problem FFMpeg produces?