Correct Replay serial number shows as Invalid
My copy of Replay 1 has defaulted back to 'free trial has expired' mode, after having used a valid serial number for 6 months. When entering the correct serial number again to re-activate it, I get a dialogue box with 'UL_AdminFormTitle', 'ULAdminRequiredNotice', 'ULAdminVistaNotice11'. This is followed by a message saying 'Invalid Serial Number'. I have never seen any of these messages before.
Can anyone help explain what's happened?