ACP/Maintenance/Database Backup must refer to an earlier version of vb.
I use this method for backing up:
http://www.vbulletin.com/docs/html/m...nce_ssh_backup
I recently stumbled upon
vBulletin Cron Based Database Backup which looks like a good way to automate backups.
Haven't tried it but I've used several of Paul's other mods over the years, they're all great.