some help with dmx model format

Hello again facepunch forum!

I want recompile model from SFM to Gmod, but model source files in dmx format. As i know i can use them in compiler just like normal .smd, but it say that model have too many flexes. Please tell me, how i can edit .dmx model? I read about comand line tool called dmxedit, but i dont understand how it should work. When i try to launch it, window of program closed in few seconds.