I just build my own map and for some reason the AI will not start building.
What could it be? I checked several tutorials and did everything.. Still no building from the AI's

I attached the file in a zip.. maybe anyone could check what the hell I'm doing wrong

Thnx

  Nederland.zip (133kb) downloaded 9 time(s).

That's one wide map!
First look at base 1 with map boundary line showing. You'll see that what you intended to be the back door and flank pathway (elevation wise) fall outside the map boundary line. Consider redoing the hills or repositioning the map so that your paths are on the map.

Because of the scale of things it can be hard to tell how big your bases are. Over each start location place the civilian object tempBuildingSize so you can see how big the inner perimeter should be. It doesn't need to be square but should be around this size so adjust the polygons you have. At this point also make sure you have a supply dock (or two) within this area. This is more than likely the reason the AI won't build. You can remove the tempBuildingSize objects when done.

Re-position your outerperimeters so they go around the innerperimeter areas without over lapping the innerperimeter OR going outside the map boundary line. Look at the map from a top down view if needed.

The Combatzone should be renamed as such without a space in the name and moved between the bases, adjusting it so it doesn't overlap the outerperimater areas of the bases.

Redo or move your pathways so that they start in the CombatZone and end in the Innerperimter of each base.

See my post on this topic of areas and pathways  and these sections  of the reviewer guidelines might also help.