Demigod is already running error!
If you have Forged Alliance running :P
from 
Demigod Forums
Demigod Forums
As the title state it seems Impulse wont launch Demigod saying its already running if you have forged alliance running 
Ok you can say its pretty normal to play only 1 game at once (and you're right) but the error message throwed me off a little till i figured it out that was the problem
Hope it helps