Can't find PlayerGui trying to get the player from the character?

Simple, step on a brick and a GUI clones into your PlayerGui from Replicated Storage. 

For some reason it always says that on line 7 the attempt to index a local "human" is nil? How? I'm missing something pretty simple here and I cant figure out what it is. I've tried multiple workarounds all of them have issues finding the PlayerGui.

local t = false

script.Parent.Touched:connect(function(hit)
	if t == false then
		t = true
		wait(1)
		local human = game.Players:FindFirstChild(hit.Parent.Name)
		local jo = game.ReplicatedStorage.JOBS.Cashier:Clone(human.PlayerGui)	
		script.Parent.Transparency = 1
		script.Parent.CanCollide = false
		t = false
		wait(600)
		script.Parent.Transparency = 0
		script.Parent.CanCollide = true
	end
end)

Any help is greatly appreciated this is getting to me.

The Touched event fires whenever something touches the specified object. Perhaps it wasn't a player that touched the object when the event fired? That would make line 7 nil.

Check if 'human' exists before proceeding with the code.

Also, you need to set the Parent property of the cloned object. Supplying an argument to the Clone function when you're invoking it as a method does nothing.

local db = false
local cashier = game.ReplicatedStorage.JOBS.Cashier

script.Parent.Touched:connect(function(hit)
	if not db then
		db = true
		 wait(1)
		local human = game.Players:FindFirstChild(hit.Parent.Name)
		if human then
			local jo = cashier:Clone()
			jo.Parent = human.PlayerGui
			script.Parent.Transparency = 1
			script.Parent.CanCollide = false
			wait(600)
			script.Parent.Transparency = 0
			script.Parent.CanCollide = true
		end
		db = false
	end
end)

I doubt it errors on line 7, it probably errors on line 8 when you try to index a "human" that you failed to find. Try using more checks to make sure the toucher is a player. By the way , "Clone" does not take a parameter; you must parent it yourself.

local t = false

script.Parent.Touched:connect(function(hit)
	if t == false then
		t = true
		wait(1)
		
		local char = hit.Parent
		--very useful!
		local human = game.Players:GetPlayerFromCharacter(char)
		
		if human then
			local jo = game.ReplicatedStorage.JOBS.Cashier:Clone()
			jo.Parent = human.PlayerGui
			
			script.Parent.Transparency = 1
			script.Parent.CanCollide = false
			t = false
			wait(600)
			script.Parent.Transparency = 0
			script.Parent.CanCollide = true
		end
	end
end)