fixes influence map for map buildings

OpenRa.Game/Game.cs

@@ -52,13 +52,13 @@ namespace OpenRa.Game
 			treeCache = new TreeCache(map);
 
 			foreach( TreeReference treeReference in map.Trees )
-				world.Add( new Actor( treeReference, treeCache, map.Offset ) );
+				world.Add( new Actor( treeReference, treeCache, map.Offset ) );
+
+			BuildingInfluence = new BuildingInfluenceMap(world, 8);
 
 			LoadMapBuildings( mapFile );
 			LoadMapUnits( mapFile );
 
-			BuildingInfluence = new BuildingInfluenceMap(world, 8);
-
 			pathFinder = new PathFinder(map, terrain.tileSet, BuildingInfluence);
 
 			network = new Network();