shogun icd error

i have a g\way p4 1.4 128 mb ram raedon ve 64mb g\card.when i try to run shogun i get error shogun caused fault in shogun icd.can get it to work if i disable direct draw run game re-enable d\draw,but it runs like treacle,with most of the mouse controls not working.i have heard that i could edit the system ini file to get it to work,any help would be much appreciated