not really, I had the same problem when I started playing and making maps.
single player.
anyways, change it from where it says "melee" to "use map settings" under game type when you go to actually create the game.
btw I know ur next question is going to be "why dont the computers move?" heres the 'walkthrough' for that: (im gonna save this...)
THE COMPLETE NEWBIES' "MAKE COMPUTER MOVE" WALKTHROUGH!!!
first, go into ur map with editor. change the layer to "location layer" from where it says "terrain layer" along the top of the editing screen. now, drag a box over the computers starting building. you should make the main building and miners and set it as a specific race, for simplicity. now, go to the top where it says "file".. "edit".. and hit scenario. hit triggers. hit "new" on the right of the window that pops up. select the player of the computer. hit next. hit create new condition. select always, hit ok, and hit next onto actions. this you find "run AI script at location." click where it says "script" underlined in blue and change that to Expansion (RACE) Campaign (DIFFICULTY), for example, expansion zerg campaign insane. hit ok on that, then select location. there should be the list of locations, and probably just "anywhere" and the location you just made. select the location that is over the starting area, "location 0" if you never renamed it. hit ok, hit ok again, finish, close the trigger window, save the map, and you can play UMS with the computers acting like they do in melee
bolt, you can save this if you want, lol.. what you think?