Lua hooks needed!

[xoft]

You need to first check if you're getting a Player at all - compare to nil. And don't compare to booleans, that is bad practice and can lead to errors (in C/C++, it is possible that "true != true")

Code:

function OnExecuteCommand(Player, CommandSplit)
  if (Player == nil) then
    return false;
  end

  if (Auth[Player:GetName()]) then
    return false;
  end

  if (CommandSplit[0] ~= "/login") then
    return true
  end
end