MySQL backups fail with "Failed to connect to database to lock tables before backup" errors. (94115)

MySQL backups of some or all tables can fail with errors similar to the following:

Error 2012/06/11 09:03:45 3827 Data Plugin MYSQL-CLIENT Failed to connect to database 'dbname' to lock tables before backup. (null)

The user configured for backing up MySQL plugin does not have the permissions required to lock the database, OR, there is another application that is preventing the user from locking the tables.

Verify that there are no other 3rd party applications that already have locks on the database or tables. Certain applications obtain exclusive locks, and cannot be running while NetVault backs up or restores the database.

Make sure the user ID has the correct permissions to lock the database, and read and write to the database for backups and restores.

Verify the user ID's permissions by running the following SQL statement where USERID is the same as the one configured in the NetVault plugin.
mysql> SHOW GRANTS FOR 'USERID'@'localhost';

Quest recommends that the user ID has "SUPER" privileges.

More details of this command can be found here - http://dev.mysql.com/doc/refman/5.6/en/show-grants.html
More details of the various privileges can be found here - http://dev.mysql.com/doc/refman/5.6/en/grant.html#grant-privileges