Every time I finish a mission (and sometimes when loading a new game) my game will crash.

I have Endless Universe, and am playing the Dark Avatar campaign, but from the Twilight of the Arnor launcher (so I get all the extra bits from the campaign). The first couple of missions played fine, but ever since the third one, the game crashes every time I finish a mission. Thankfully I can just go into the Campaign menu to continue the mission.

Any idea what might be going on?

I am running Vista 32 on a Quad Core with 4GB RAM.