company of heroes problems

hey just a quick question when playing company of heroes i have to download a patch but it keeps saying theres an error and i have to press ok and it starts from were it stopped at the error which id say isnt normal.after i got it to install it told me i had company of heroes opposing fronts the expansion for coh installed but i hadnt installed it yet and when i ran opposing fronts it said it was installed but i couldnt use any of the campaigns...im putting it down to windows vista as i know it causes problems with some games anyone have any ideas on how to fix this? thanks for your time