attempt to get length of a nil value?

I Have This Code Where It Animates Text And I Requires It To Have A Waiting Time For Each Word To Appear. Anyway. Its Saying There is A Nil Value Somewhere Please Leave Your Suggestions Below.

Quick Disclaimer Im Not Using Roblox Functions Inside Strings Its Just For Game Design. Thats All :D

local text
local preset = "var FinNearestConnect = FindFirstObjectName('SlidingDoor') var2 Door = FindNearstConnect:FinalizedString('Door') Door:GetAuthorize(Owner) if not Auth then \Execute Door:GetFinalAuthorization('Owner') if not auth then return \Excute Require(5967169491,Sys)"

local preset2 = "/Execute Door.Push = Pos.Y - 5 X 90,Auth:Complete('Owner') println('open') anglang=C"
for i = 1, #text do
	script.Parent.TextLabel.Text = string.sub(text,1,i)
	wait(0.05)
end

script.Parent.Parent.Parent.Parent.Keyboard.ClickDetector.MouseClick:Connect(function()
	script.Parent.Image.Visible = false
	script.Parent.TextLabel.Visible = true
	text = "require(13677U123,SYS)"
	wait(2)
	text = "downloading... "
	wait(5)
	text = preset
	wait(2)
	text = "downloading final auth..."
	wait(3)
	text = preset2
	
end)