If you're using the LocalMap entry in UTEngine.ini instead of specifying starting settings on the server's command line, you may have noticed that, frustratingly, the game's processing of this line has several bugs associated with it. Luckily, though, with just a few minutes' work and knowledge of how to address the bugs, it is fairly easy work around them.
The biggest bug is that the game often only reads up to a period (".") somewhere in the line, and then stops. Periods are common, such as in the specification of the DefaultGame ("UTGame.UTDeathmatch" by default), and you will also see them in many mutator specifications, so this is a commonly stumbled-upon condition. Our workaround for this is to add garbage characters to the end of the LocalMap line -- often something very simple such as a space and then another period character is all that is needed. Sometimes more characters, different random characters, or additional "." characters are required.
We don't see it nearly as often, but the LocalMap line is also processed incompletely when it is particularly long. It is a good idea to try to keep it short, and minimize the amount of variables it specifies (putting them elsewhere when you can). Some variables, like "NumPublicConnections" and "LockedServer", are no longer necessary (as of patch 1.1) and can be safely removed without re-adding them in another file.
We have also noticed that a question mark ("?") is necessary at the end of the line, before the garbage characters, for the last variable to be processed correctly. Otherwise, the game will think the garbage characters are being assigned to the last variable.
If you're not sure how much of your LocalMap line is being read by UT3, just open up the UTGame/Logs/DedicatedServer.log file and look for the LoadMap entry, which will usually be near the end of the log if the server was recently started. If you see only a partial line there, try adding more garbage characters to LocalMap (for instance, " as.ad.sfa.asdf.as"), and, if that does not work, try finding ways to shorten the line.