Ok, so I got the SupCom map editor, and put it into the SupCom bin. At first it never started up, so I ran it in Administrator, and in Combatability mode for Windows XP Service Pack 3. So, it then booted up, but, when I tryed to open a new map, or a map from a game (Original or FA) then it crashed. I ran a troubleshoot, and it said to use Xp Service Pack 2, which I then did, but that did not help the problem. I was wondering if anybody else had that same problem, and how to solve it.

Said this here too

You may be having a version mismatch. Have you updated to the latest version of Supreme Commander and the latest version of the editor? Go here, do a fresh install, and use the retail to current download if in doubt.

You can go here to download the latest map editor under 'tools' if you aren't using the vault.