The postfix service is set to use the ispconfig account not the root account. Is there any other place I need to be change the root password besides
No, thats the only place. All other services (postfix, dovecot or courier, pure-ftpd and the ispconfig interface and server script) are using the user ispconfig. The mysql root password in mysql_clientdb.conf is only used to create new mysql users and databases from within ispconfig.
Do you get any errors in the mysql log files?