I'm having difficulty understanding how this is supposed to work.  I've installed the basic toolkit, created the necessary mod folder, filled it with the virgin entity files that came with the toolkit, and the game crashes when I try to enable the mod.

I've tried a few different approaches, as well.  I deleted everything from the <modname>/gameinfo folder except a single virgin entity file and it crashed.  I tried a single entity file with a single variable changed, still crashes.  I tried putting no files in there.  Still crashes.

It looks straight forward enough in the modset guide.  What am I missing here?