Why wont this work?

local g = game.Workspace.GuiGive2

while true do
	for i,v in pairs(game.Players:GetChildren()) do
		if (v.Character.Torso.Position - g.Position).magnitude <= 10 and 	v.PlayerGui.Teleport.Game.Visible == false then
				v.PlayerGui.Teleport.Game.Visible = true
		end
		if (v.Character.Torso.Position - g.Position).magnitude >= 10 and v.PlayerGui.Teleport.Game.Visible == true then
			v.PlayerGui.Teleport.Game.Visible = false
		end
	end
wait()
end

It's suppose to work so when someone comes near the brick it shows a gui

g = game.Workspace.GuiGive2

Change this line to

g = game.Workspace["GuiGive2"]