I've found some information from old game magazine that Incubation (propably addon - Wilderness Missions) have editor which allow people to make own maps and missions.
Did GOG release include that editor?

Yes, the editor is included. I should warn you, however, that having tried it once before I have no idea how it actually works. :)

Game installed, click on Editor.exe and... nothing happen.
Even more - there is no "ManualEditor" file for more details.
And google have nothing.

EDIT.
Ok, Editor.exe doesn't work because real editor is "iDesigner.exe".

Well, see no manual for editor but - it's not look difficult. Some trials & errors and maybe it work and made something decent.

Its a typical editor of that time. Reminds me the editors they used for Quake or Unreal.

But this was over a decade ago so I could be wrong.

Isn't there a way to make it work or some other editor that does?

The editor works.

What are you having problems with?