Why wont this change the decal?

So whenever i press the button...the decal just disappears and nothing comes back. Here is the script:

local button = script.Parent
local gate = game.Workspace.Gate
local gt = game.Workspace.Gate.Transparency

function onClick()
	gate.Transparency = 1
	wait(.1)
	gate.Transparency = .9
	wait(.1)
	gate.Transparency = .8
	wait(.1)
	gate.Transparency = .7
	wait(.1)
	gate.Transparency = .6
	wait(.1)
	gate.Transparency = .5
	wait(.1)
	gate.Transparency = .4
	wait(.1)
	gate.Transparency = .3
	wait(.1)
	gate.Transparency = .2
	wait(.1)
	gate.Transparency = .1
	wait(.1)
	gate.Transparency = 0
	gate.CanCollide = true
	game.Workspace.GateScreen.Decal.Texture = "http://www.roblox.com/asset/?id=173957815"
	end

button.ClickDetector.MouseClick:connect(onClick)