Loading missions in Greywolves

Hi, I hope someone can help me. I've just done a fresh installation of SH3 after a while playing other games and out of curiosity I also loaded Gameshadow. To my utter surprise I found they included a full install of Greywolves so I downloaded and installed this also. Now when I come to start a mission or career it loads about 85% and locks up so I have to reboot. My system is by no means lo-spec but I always reduce settings first to avoid any lag. Is there an easy solution to my problem because it is beyond my limited computer skills. Please help