What I would do if you know sql is edit /etc/mysql/my.cnf, remove the # in front of the 'log' line, and then reboot, try to browse music, and look in /var/log/mysql/mysql.log to see the query that is select * FROM pluto_media.File. If the records are in the DB, something else is going on.
Also, in the media browser, click the 'sort' and try sorting by filename as well as artist/title.