The language file lang/en_utf8/auth.php specifies in the $auth_dbpasstype variable the path to a file called auth/db/cron.php (which doesn't exist), when it should specify a file called auth/db/auth_db_sync_users.php.

This should be checked in all the language files (I have only checked the 'master' en_utf8 lang files).

Saludos. Iñaki.