Argument 1 missing or nil on firing client?

So the thing is that when the player touched the object, it fires the remote event for the client and once fired, a gui will show, Any help?

-- Main Script coded in a Script

local function acti()
	_G.Wall1.Disabled = false
	_G.Wall2.Disabled = false

	game.ReplicatedStorage.RemoteEvent:FireClient()
end


script.Parent.Touched:Connect(acti)

-- Receiver coded in a Local Script:

local function activateSpook()
	script.Parent.Enabled = true
end

game.ReplicatedStorage.RemoteEvent.OnClientEvent:Connect(activateSpook)

When using

:FireClient()

you have to add a player in the brackets so the computer knows who to fire the event to. Like so:

:FireClient(player)