I downloaded Alien Swarm, and when I run it everything in the main menu works fine. But whenever I try to connect to a server- even a dedicated server of my own creation- the progress bar is nearly complete and then the game exits. No error message, nothing. I can't even play offline practice mode. Has this happened to anyone else, and do you have ideas on how to fix it? (Yes, I am aware that it could be due to the sheer number of people trying to connect.)