I'll be working on an update for 10.5.x Mac OS X users soon.
Also, in order to setup multiplayer, just get everyone that wants to play into one lobby using the Extinction map, and have them all swap the same map files.
That's accomplished using Terminal right? I'm sorry I'm such a computer noob =\
so i typed in
open "/Applications/Starcraft II Beta/Starcraft II.app" args run "/Downloads/build order tester v2.4.SC2Map"
into the terminal line, pressed enter, and nothing happened again.
If NOTHING happens at all, then something's gotta' be wrong with your SC2 or Mac OS X install.
Your path for the map though looks wrong, too. "/Downloads/build order tester v2.4.SC2Map" would be what you're looking for.
Though SC2 should at least open even if that's wrong.
The only reason this could happen is if your Starcraft App setting is wrong. By default this is "/Applications/Starcraft II Beta/Starcraft II.app", but you can change it to point to the right .app under the Settings tab.
As I said, 1.2 is only a quick fix for Windows XP enUS clients that maintain the default path of C:\Documents and Settings\USERNAME\Local Settings\Application Data\. If the path is any different at all, it'll fail.
Edit #2: I will be updating MapCraft again with a rewrite soon to fix Windows support once and for all, and enhance overall usability.
I've added 1.2 for Windows XP users on the downloads page. This may solve issues a lot of you had. It's not a proper fix but it'll work for probably 98% of XP users. I've gotta' learn JNI and call the Windows API to do it properly later. It won't work if your path isn't completely standard, or if you're not on an English build of Windows.