Me and at least 3 others according to discussion on Steam forum are unable to launch game from Steam and just get the generic error message in topic title.
To raise a Support Ticket you need to know the server and as I can't get in to look I don't know which it is. Never felt the need to know uo till now.
So 2 things:-
1. Anyone know how to determine which server you are on from Steam client if actually possible?
2. Any other Seam users having same issue?