[Solved]Why won't it work?

Indent in a more organized fashion! You'll be denoted as a more organized and professional scripter.

ToolName = "TMP" -- Exact name of the weapon/tool
RespawnTime = 6
Debounce = false

script.Parent.Touched:connect(function(hit)
	if Debounce == false then
		Debounce = true
		p = game.Players:playerFromCharacter(hit.Parent)
		if p == nil then
			return
		end
	else
				Wep = game.Lighting.TMP:Clone() --Change TMP to the name of your weapons
				if p.Backpack:findFirstChild(Wep.Name) ~= nil then
					return
				end
			else
				Wep.Parent = p.Backpack
			end
		end
		wait(RespawnTime)
		Debounce = false
	end
end)
-- I just realized your script contained an error. Nope nope nope nope nope nope...

Let's redo the script. The objective here is to, given the ToolName, clone the desired weapon and place it in the toucher's backpack - assuming that it is a player.

ToolName = "TMP"
RespawnTime = 6
Debounce = false

script.Parent.Touched:connect(function (Hit)
	if not Debounce then
		Debounce = true
		-- Where the cloning takes place
		wait(RespawnTime)
		Debounce = false
	end
end)

Let's wrap the "if" statement (with the Debounce as its condition) into another "if" statement that makes sure that the toucher is a) a valid character, b) is part of a player instance, and c) is (preferably) alive.

ToolName = "TMP"
RespawnTime = 6
Debounce = false

script.Parent.Touched:connect(function (Hit)
	local HumanoidIsFound = Hit.Parent:FindFirstChild("Humanoid")
	local PlayerIsFound = game.Players:GetPlayerFromCharacter(Hit.Parent)
	if Hit.Parent and HumanoidIsFound and HumanoidIsFound.Health > 0 and PlayerIsFound then
		if not Debounce then
			Debounce = true
			local Weapon = game.ServerStorage:FindFirstChild(ToolName)
			if Weapon then
				local newWeapon = Weapon:Clone()
				newWeapon.Parent = PlayerIsFound.Backpack
			else
				print("No such weapon named as " .. ToolName .. " in game.ServerStorage.")
				Debounce = false
				return
				-- In my opinion, lines 15-18 are pointless, but it's good to know what's wrong with your script. This is here just in case if the weapon does not exist.
			end
			wait(RespawnTime)
			Debounce = false
		end
	end
end)

Any questions? Comments? Feel free to ask.