don't crash on find_nodes_in_area for big areas

mod_areas.lua

@@ -11,8 +11,9 @@ function creative_regions:get_areas_area_size(areas_area)
 	local pos1 = areas_area.pos1
 	local pos2 = areas_area.pos2
 	local x = math.abs( pos2.x - pos1.x )
-	local z = math.abs( pos2.z - pos1.x )
-	return x*z
+	local z = math.abs( pos2.z - pos1.z )
+	local y = math.abs( pos2.y - pos1.y )
+	return x*z*y
 end
 
 if minetest.get_modpath("areas") then
@@ -23,6 +24,11 @@ if minetest.get_modpath("areas") then
 		local area_id = "a"..tostring(id)
 		creative_regions.set_region_privs(area_id, nil)
 		creative_regions.save_regions()
+		if creative_regions:get_areas_area_size(area) > 4096000 then
+			minetest.chat_send_player(owner, "[creative_regions] area " .. area_id .. " too big. Can't search for Protector Blocks")
+			minetest.log("warning", "[creative_regions] area " .. area_id .. " too big. Can't search for Protector Blocks")
+			return
+		end
 		local protectors_in_area = minetest.find_nodes_in_area(area.pos1, area.pos2, {"creative_regions:protector_nofly", "creative_regions:protector_arena"})
 		for _, pos in ipairs(protectors_in_area) do
 			local meta = minetest.get_meta(pos)