WP-DBManager Plugin Can’t Find Mysql Path

I solved this with help from the main StackOverflow site. One of the commenters suggested that the open_basedir directive might be set in php.ini – and that was the issue. Here is the open_basedir setting:

open_basedir = "/var/www/vhosts/lifering.org/:/tmp/"

I created a hard link mysql (could have been a symlink) to /usr/bin/mysql in the /tmp directory and then changed the MySQL path statement in WP-DBManager to read /tmp/mysql. The error message cleared immediately.