[clemato]

Well, I belive I found a solution, albeit a strange one...

I got the idea of installing another Quake 3 engine based game, seeing if it would crash like MOHAA. (Return to Castle Wolfenstien.)
This game did not crash, and so in frustration I gave MOHAA one last try. And whadda ya know, no more lockups... well there was one, but I was also fooling around with the video resolution and properties at the time. (and it seems having volumetric fog on also makes the game a tad unstable.)

So my advice is, install a game that uses the Quake 3 engine (preferably Return to Castle Wolfenstien, because it worked for me.) Then install MOHAA, and try to play it (dont alter any video properties, just install and play.) Then once you have established that MOHAA is stable, start tweaking the video properties, if it crashes after a tweak, notch it right back to where it was.

Good luck, and happy hunting!