Some more information would be nice. What os are you on? what version of the editor do you have? where did you get it from? has the editor or supertux worked before? That sort of information.
Some people are like slinkies... not really good for anything, but you still can't help smiling when you shove them down the stairs.
I have now Windows 8.1 64bits, the version is r6694 and i got from http://supertux.lethargik.org/wiki/User:Rgcjonas, in Windows 7 i had it working but its no longer working in windows 8.1 and i have SuperTux 0.3.5a