Orgrimmar2.wmo dont open in blender

[Farrarie]

when I try to import this wmo in blender I get this error =
here is the wmo
World.zip

here is the error
Traceback (most recent call last):
File ":\blender-2.78c-windows64\2.78\scripts\addons\io_scene_wmo_init_.py", line 163, in execute
import_wmo.import_wmo_to_blender_scene(self.filepath, self.load_textures, self.import_doodads, self.group_objects)
File "\blender-2.78c-windows64\2.78\scripts\addons\io_scene_wmo\wmo\import_wmo.py", line 56, in import_wmo_to_blender_scene
group.load_object(obj_name, import_doodads)
File "\blender-2.78c-windows64\2.78\scripts\addons\io_scene_wmo\wmo\wmo_group.py", line 458, in load_object
mesh.polygons[i].material_index = material_indices[mat_id]
KeyError: 0

location: :-1