run/time error 5

I just noticed this same error after installing a new hard drive, windows 7 and trying crossfire for first time. Turns out my problem was just to do with the user account control. You need to make sure you click Yes to the message and allow the patcher_cf.exe to work otherwise you will get this error.

Maybe you could also try turning off the user account control part of windows. To do this go to the Control Panel and click User Accounts. Then go to Change user account control settings at the bottom. Put the setting on the lowest (Never Notify) when you want to play crossfire and change it back when you have done.