What am I doing wrong?

local Player=game.Players.LocalPlayer
repeat wait() until
game.Players.LocalPlayer
game.Players.PlayerAdded:connect(function(Plr)
	AllPlayers=Plr.Parent:GetChildren()
end)
repeat wait() until
Player.PlayerGui.ScreenGui

local Frame=Player.PlayerGui.ScreenGui.Frame
--~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
AllPlayers.Chatted:connect(function(Msg)
	Frame.Ten.Text=Frame.Nine.Text
	Frame.Nine.Text=Frame.Eight.Text
	Frame.Eight.Text=Frame.Seven.Text
	Frame.Seven.Text=Frame.Six.Text
	Frame.Six.Text=Frame.Five.Text
	Frame.Five.Text=Frame.Four.Text
	Frame.Four.Text=Frame.Three.Text
	Frame.Three.Text=Frame.Two.Text
	Frame.Two.Text=Frame.One.Text
	Frame.One.Text=Msg
end)

I'm trying to make a chat system like the one that is already on ROBLOX, except longer. This is in a localscript inside of StarterPack. The error I get is Attempt to index global 'AllPlayers' (a nil value), and the error is on line 12

Try this:

local Player=game.Players.LocalPlayer
repeat wait() until
game.Players.LocalPlayer
game.Players.PlayerAdded:connect(function(Plr)
    AllPlayers=Plr.Parent:FindFirstChild:GetChildren()
end)
repeat wait() until
Player.PlayerGui.ScreenGui

local Frame=Player.PlayerGui.ScreenGui.Frame
--~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
AllPlayers.Chatted:connect(function(Msg)
    Frame.Ten.Text=Frame.Nine.Text
    Frame.Nine.Text=Frame.Eight.Text
    Frame.Eight.Text=Frame.Seven.Text
    Frame.Seven.Text=Frame.Six.Text
    Frame.Six.Text=Frame.Five.Text
    Frame.Five.Text=Frame.Four.Text
    Frame.Four.Text=Frame.Three.Text
    Frame.Three.Text=Frame.Two.Text
    Frame.Two.Text=Frame.One.Text
    Frame.One.Text=Msg
end)

For line 5, I added "FindFirstChild" so that the script has time to find the Player's items.