I get this message too, playing in GameSpy. It is mainly other people who get it when they are joining games that I host, just when they enter the game setup room. One player says that he associates this problem with not being able to re-enter the game later. I'm running patch 1.52 with no mods. Others running 1.52 get the message. Sometimes the game will run, sometimes not. Sometimes the map will load but no one can make their first unit moves -- units seem frozen on the map, but otherwise the interface seems intact. Sometimes I cannot join games and get a CTD, with the message that my save file is being protected to ensure that the contents of my mod folder are not changed. I'm not running any mods and my mod folder is empty. Others report that my game is showing in the forum as firewalled, when both my Windows XP firewall and my router firewall are both down (not operating) AND have been programmed with the correct port numbers found elsewhere in this forum. I am an A+ certified PC tech and a lifelong strategic gamer, in great admiration for Firaxis folks and wanting to help in any way I can. Please, if you know, or find out, anything about these problems, send me a direct email. I desperately want to play this game with my kids on home network, and with our friends over GameSpy and direct IP. Firaxis, keep up the good work! I know you will resolve these problems. God, but it's frustrating!