Wish i could help..
prepare me a build (open source of course). i'm on my way right now for a new PSU ( i sure hope that's what the problem is). When my pc is set up again, i'll ask you to upload that build somewhere.
In the meantime, since you've narrowed down that this is a problem with the model, try playing around with it a bit.. check out its animations names.. that the origin point is always at the same spot.. things like that. I've been using MD5 models for intense pathfinding all the time, so i know there's no problem with the format itself..
Cheers dude,
Aris