Script works fine in studio but breaks in game with no error message. why?

ok this has stumped me and i have no idea how to fix it. Its supposed to be a custom loading screen i designed for my game. and it works great. i go to test it in game(not in studio) it does nothing and no error message. help?

local prog = 0

script.Parent.Parent.Parent.Parent.PlayerAudio.IntroMusic:Play()
script.Parent.Parent.Parent.Parent.Parent.CameraMinZoomDistance = 10
local player = script.Parent.Parent.Parent.Parent.Parent.Name
workspace:WaitForChild(player).Humanoid.WalkSpeed = 0


while wait() do
	prog = prog + 0.5
	script.Parent.Size = UDim2.new(prog/100, 0, 0.1, 0)
	script.Parent.Parent.LoadingLabel.Text = ("Loading...   " ..math.floor(prog*2).. "%")
	if prog == 80 then
		wait(1)
		script.Parent.Parent.LoadingLabel.Text = "Loaded!"
		
		local A = script.Parent.Parent.LoadingLabel:Clone()
		A.Name = "LoadedLabel"
		A.Parent = script.Parent.Parent
		
		script.Parent.Parent.LoadingLabel.TextTransparency = 1
		
		
		script.Parent.Parent.Parent.Start:TweenPosition(UDim2.new(0.229, 0,0.051, 0),1,7,3)
	end
end