Game crash

[Conq]

I'm running Dom2 on an older computer with a bunch of junk on it, so the game runs pretty slow. I've been playing a large sp game and im at around turn 100 so there is a lot of stuff going on in the map.
Recently the game has been crashing and I get a window that says:

Nagot gick fel!
unit -1
getmaxhp: bad unr

any ideas?

thanks