Okay, so I made a script that would create a bool value to check if the game intro is ran. Here is the script for that:
game.Players.PlayerAdded:connect(function(player)
local IntroRan = Instance.new('BoolValue', player)
IntroRan.Name = 'IntroRan'
IntroRan = false
end)
So I checked the location when I went into play mode, and I saw the Boolvalue where it should be (Players.LocalPlayer). I also created local script to check if the bool value is true or not, and if it is, it will enable a script. Here is the script for that:
local player = game.Players.LocalPlayer
local introran = player.IntroRan
while true do
wait(0.05)
if introran == true then
player.PlayerGui.Warning.LocalScript.Disabled = false
end
end
It looks like the scripts should work but it doesn't. In the script output, it says that the bool is not a valid member of player. What's wrong?

2 comments
Ok, thank you, also its in a loop so that it keeps checking (is there another way to do that?).
http://wiki.roblox.com/index.php?title=API:Class/BoolValue/Changed