Ladder texture was renamed.

Due to upstream minetest_game changes.

nodes.lua

@@ -280,7 +280,7 @@ minetest.register_node("maptools:climb", {
 	description = S("Climb Block"),
 	range = 12,
 	stack_max = 10000,
-	inventory_image = "default_steel_block.png^default_ladder.png",
+	inventory_image = "default_steel_block.png^default_ladder_wood.png",
 	drawtype = "airlike",
 	walkable = false,
 	climbable = true,
@@ -341,9 +341,9 @@ minetest.register_node("maptools:ladder", {
 	range = 12,
 	stack_max = 10000,
 	drawtype = "signlike",
-	tiles = {"default_ladder.png"},
-	inventory_image = "default_ladder.png",
-	wield_image = "default_ladder.png",
+	tiles = {"default_ladder_wood.png"},
+	inventory_image = "default_ladder_wood.png",
+	wield_image = "default_ladder_wood.png",
 	paramtype = "light",
 	paramtype2 = "wallmounted",
 	walkable = false,