My code couldn't give hats with decal to an NPC?

local du2 = game.Workspace.Dummy2

-- This is just a piece from my function so nothing necessarily to add beforehand

local hat = game:GetService("InsertService"):LoadAsset(13745548):GetChildren()[1]
du2:AddAccessory(hat)
hat.Name = "LongHairHeadBandBrown"
game:GetService("InsertService"):LoadAsset(860143307, 911686934).Parent = du2.LongHairHeadBandBrown

Error output:

InsertService cannot be used to load assets from the client

(I wanted this script to give an available NPC named Dummy2 (du2) a hat, also inserting two decals into it.)

Edit:

du2 = script.Parent

if du2.Head.Transparency == 0 then
	hat = game:GetService("InsertService"):LoadAsset(13745548):GetChildren()[1]
	du2:AddAccessory(hat)
	hat.Name = "LongHairHeadBandBrown"
	game:GetService("InsertService"):LoadAsset(860143307).Parent = du2.LongHairHeadBandBrown
	game:GetService("InsertService"):LoadAsset(911686934).Parent = du2.LongHairHeadBandBrown
	end

However, this is in the GuIButton so I'm clearly not sure.