My gun script is broken sometimes?, and output says attempt to index nil with "FindFirstChild"

local debounce = false

script.Parent.RemoteEvent.OnServerEvent:Connect(function(player,hit,target)
	if debounce == false then
		debounce = true
		local newpart = Instance.new("Part",workspace)
		local dist = (hit-player.Character.HumanoidRootPart.Position).Magnitude
		newpart.BrickColor = BrickColor.new("Fire Yellow")
		newpart.Anchored = true
		newpart.CanCollide = false
		newpart.Size = Vector3.new(0.2,0.2,(hit-script.Parent.Handle.Position).Magnitude)
		newpart.CFrame = CFrame.new(script.Parent.Handle.Position,hit) * CFrame.new(0,0,-dist/2)
		script.Parent.Handle["Glock 21 Gunshot"]:Play()
		spawn(function()
			for i = 1,10 do
				newpart.Transparency = i/10
				if i == 10 then
					newpart:Destroy()
				end
				wait(0.05)
			end
		end)
		
		if target ~= nil then
			if target.Parent:FindFirstChild("Humanoid") then
				if target.Parent ~= player.Character then
					target.Parent.Humanoid:TakeDamage(script.Parent.damage.Value)
					end
			end
end
		wait(script.Parent.Firerate.Value)
		debounce = false
	end
end)
while wait() do
	script.Parent.Firerate.Value = script.Parent.OriFirerate.Value - (script.Parent.OriFirerate.Value/100*game.Workspace.FirerateMul.Value)
	script.Parent.damage.Value = script.Parent.Oridamage.Value + (script.Parent.Oridamage.Value/100*game.Workspace.DamageMul.Value)
end