vlc 0.8.4 in ubuntu dapper won't play matroskas(mkv)

[abrakatabra]

I installed vlc_0.8.4.debian-1ubuntu6_i386 and I hope it'sdependencies using an addon cd on a Ubuntu 6.06 LTS dapper.

The avi files play well(although not in the quality I experience on Windows VLC Player. There is some instantaneous discontinuities(stills)).

DVDs play reasonably well.

The problem is with matroska(.mkv) files. I have only two of them(I believe they are highly compressed ones). I play them well on VLC in windows. But can't play them in ubuntu vlc. The videowill start with a highly distorted picture almost in slow motion.Sound is ok.

Now in my ubuntubox I have no matroska drivers but I think vlc doesn't depend on external drivers?

I tried(lacking the knowledge) to change some settings by chance,I choosed matroska demuxer etc etc but nothing happened. Then I used reset settings totheoriginal ones but againnothing...

Can you help?