Operation Arrowhead CTDing

[Goose404th]

Hello new to Operation Arrowhead and my CTD problem is happening everytime i go to jump into a mission or start the Operation Arrowhead campaign. I have regular ARMA 2 and it runs great any ideas?

My system specs are this:
Win 7 64 bit
Intel i3 Dual core 2.93
Geforce Darknight GTS250 1gig memory
4 gig of onboard memory
running at 1333fsb