Try to use FPlay as video player. All you have to do:
1) Download it (from archive of additional programs, for example:
http://kolibrios.org/en/download.htm )
2) Unpack it to some hard drive where your files are visible from Kolibri
3) Launch it from shell/run with "/hd0/2/full/path/to/fplay /hd0/3/full/path/to/video/video.h264.mp4"
OR
Open /rd/1/file managers, and edit config file for your favourite file manager (say, eoilte, kfm, kfar), to set associations, like
mp4=/hd0/2/path/to/fplay
avi=/hd0/2/path/to/fplay
etc
OR
Try to use KolibriN package -
http://kolibri-n.org/files/KolibriN.zip
This is ISO file, afaik. So you have to burn it on CD, or unpack files from it to your HD, and then just launch "install" - this will install all dependencies for current session.