It's that time of year again. The time of year where we have to diagnose the mod and all that fancy stuff. So for those of you unaware, a few people are having problems trying to access the Unreal Construction Gametype, Ouch! The only response at this time that we can think of, Have you updated your game to version 2.1 (Patch 5) ?
Not entirely sure if this will be a guaranteed fix, it may depend on your computer, several other possible fixes that have not been tested, try running the game in compatibility mode with Windows XP SP3, and as administrator.
If you are trying to host a server and it is not working, you could head on over to Epic Games and try out the Web Admin package, it's quite handy. Utforums.epicgames.com