Seas =)
So I guess if is a map problem not a editor problem - means, if you try open other map, all works fine.
1) So try it: Open other map - editor should load everything - after try to reopen your map.
2) You created your map with the normal editor, so there must be "WorldEditTestMap" in Wc3\Maps\Test\. If your own map was the last map you saved, this WorldEditTestMap is the same map, try to open it.
3) Don't know, but if you install the Jass NewGen, try to open your map with it, if it has an success