I’m playing on Win7 x86-64. The option to run the game while inactive does not seem to work, as the game pauses anytime I switch to another window. I play using full screen enabled. Don’t have any expansions installed.
The run while inactive was designed mainly for windowed mode, partly because windows can get upset otherwise. I just tested this fullscreen in Windows 7 64 bit and with my setup, the moment I task-switch, the game gets minimised on that monitor, but then still runs. Is the game still fullscreen and pasued for you?
I have horrible feeling this sort of behavior is also graphics-card dependent. ATI card here.
I will say it does run and I am using a 4870 ATI card, 64bit.