We've been using WP-DBManager for some years; http://lifering.org is a WordPress 3.4.2 site hosted on a virtual Linux server by GoDaddy. A week or so ago I rebuilt the site from a backup in order to upgrade the O/S from CentOS 5 to CentOS 6. As part of this we had to upgrade our control panel from Simple Control Panel to Plesk 11. It also changed all our base paths. Since the upgrade, WP-DBManager says that the path to MySQL (/usr/bin/mysql) is invalid, even though that IS the correct path.
I read the earlier post on this and the link that suggests it isn't REALLY necessary to have that path. But when I try to run a manual backup it fails; and my latest automated backup was filesize 0.