the error that you showed in your previous post "XML error: not well-formed (invalid token)" is absolutely new for me.
It seems that something has "corrupted" your well-formed xml backup file !! Could you send me that backup file (privately) to make some tests with it ?
Can you send me the phpinfo page executed in your server too ? (you can execute it from the admin's Moodle main page).
TIA and ciao, Eloy