Why cant this script index its own parent?

server script:

f = false
script.Parent.MouseButton1Click:Connect(function()
    if not f then
        f = true
    for i,v in pairs(game.Workspace:GetChildren()) do
        if v.Name:match(script.Parent.Parent.Parent.Parent.Parent.Name) then
            local player = game.Players:GetPlayerFromCharacter(v)
            if player.leaderstats.Money.Value >= 15 then
            player.leaderstats.Money.Value = player.leaderstats.Money.Value - 15
            script.Parent.Parent:Destroy()
            end
            end
        end
    end
end)

on line 6 it says

Players.world_kiIIer.PlayerGui.rank.Frame.yes.yes:6: attempt to index field 'Parent' (a nil value)

why does this happen?