Attempt to index local 'gui' (a nil value?)

Please help, I'm trying to get a GUI to open when a tool is selected but it isn't opening at all. :-(

I get this error when I open the tool: OpenGUI:7: Attempt to index local 'gui' (a nil value), global LoadGui OpenGUI: Line 21

And this error when I close the tool: OpenGUI:16: Attempt to index local 'gui' (a nil value), global UnloadGui: Line 25

local player = game.Players.LocalPlayer

function LoadGui()
repeat wait() until player.Character 
if not player.PlayerGui:findFirstChild("BenOVGUI") then
gui = game.ReplicatedStorage.BenOVGUI:Clone()
gui.Parent = game.Players.LocalPlayer.PlayerGui
print("Gui placed in ".. player.Name) 
else 
gui.Enabled = true
print("Gui Enabled.")
end
end

function UnloadGui()
gui.Enabled = false
print("Gui Disabled.")
end

script.Parent.Parent.Equipped:connect(function()
LoadGui() <--?
end)

script.Parent.Parent.Unequipped:connect(function()
UnloadGui() <--?
end)

Try this code instead, make sure you have the GUI in ReplicatedStorage.

(uhh I used tabs because it looks prettier)

local player = game.Players.LocalPlayer
local playerGui = player:WaitForChild("PlayerGui")

function LoadGui()
	repeat wait() until player.Character 
	if not player.PlayerGui:FindFirstChild("BenOVGUI") then
		local cgui = game:GetService("ReplicatedStorage"):WaitForChild("BenOVGUI")
		gui = cgui:Clone()
		gui.Parent = playerGui
		print("Gui placed in ".. player.Name) 
	else 
		player.PlayerGui.BenOVGUI.Enabled = true
		print("Gui Enabled.")
	end
end

function UnloadGui()
	playerGui.BenOVGUI.Enabled = false
	print("Gui Disabled.")
end

script.Parent.Parent.Equipped:connect(function()
	LoadGui() <--?
end)

script.Parent.Parent.Unequipped:connect(function()
	UnloadGui() <--?
end)

Let me know if you have problems, I'll try to help gladly.