Virtualdub mod MKV support is kludgy......
It won't cut anything with subtitle or RV9.
You can try matroska stream editor.....
but that gonna be kuldgy as well :-/
MKV tools are still too new to be reliable anyway.
If you have divx/xvid stream + mp3 in MKV, i recommend you to demux/transmux them to elementary stream/ AVI before trying to cut them.
good luck
