Value is a nil value?

I just made a "Dig" tool that, when the player clicks on certain parts, it gives him the item from ServerStorage that a Value in the part names. I've tried a StringValue to search for the item by name, and ObjectValue to link directly to the item, but both cases give me the same error saying that it's attempting to index a nil value. Here's the block in question:

function clicked()
		if mouse.Target == nil then return end --mouse is defined earlier
		if equip == false then return end -- T/F variable defined earlier
		if mouse.Target.Name == "dgSpot" then
			local tlname = mouse.Target.Tool.Value
			-- Line below is for StringValue
			--local tool = game.ServerStorage:FindFirstChild(tlname):Clone()
			
			-- Line below is for ObjectValue
			local tool = tlname:Clone()
			tool.Parent = player.Backpack
			
		end
	end
	
mouse.Button1Down:connect(clicked)