I have the same problem, and I can't do anything with it.
Some time ago I had this problem, and one day it fixed itself. Everything was working fine for some time. Few days ago I downloaded a new resources pack for mta, and it broken my editor again. Now even reinstall doesn't help.
Is it possible to fix it?
EDIT:
If you need more info:
I'm using Windows 7 and I noticed that editor was woring properly in MTA 1.1, as long as I reinstalled it. Now both editors don't work.