Current questions and answers regarding the map editor.

Ignore the first two; it's the editor's paranoia. The first means there's no upper limit to the levels on the map, and the second means there are no rumors. This can be fixed through the map properties.
Next, there's more than one entrance (or exit?) in a group of one-way portals. If that's the intention, ignore it; if not, break the portals and exits into groups through the object properties.
Then, there are 3 cities without a specialization. This can be fixed through the object properties of the city.
And finally, one hero doesn't have an army assigned. Either fix it manually, or the game will assign one at the start. I would recommend the first option (through the object properties).