Yes, the server may be sued by the employer in this case. Whenever anyone--including an employee--costs someone else--including their employer--money due to either their negligence (or carelessness) or intentional wrongful act, the person or business which lost money due to the other person's act is entitled to compensation and may sue for it if not provided voluntarily. In this case, the employee's negligence cost the employer money(the fine and any costs from the liquor board's action); the employer may recover it from them, the same way the employer could recover its loss from the employee if the employee lost cash he or she was sent to the bank to deposit, or carelessly broke a chandilier or light fixture.