Current questions and answers regarding the map editor.

That article is quite old; it seems they were directly editing the data.pak file... You need to act a little differently. You should put these files, which Igromania says to edit, into your own zip archive (preserving all paths, meaning the archive should have the same structure as data.pak). Then, rename the zip archive to *.h5u and put it in UserMODs. If you need to work with files in an editor, the scheme is actually the same, but you shouldn't create a new archive; instead, take an existing one, specifically your map, open it with an archiver, and put the modified file in the correct location.