Hi,
In addition to the technote provided,Kindly refer the following,
Microsoft Small Business Server (SBS) 2003 includes a Monitoring and Reporting feature that is installed by default. The installation of this feature creates a named SQL instance, MSSQL$SBSMONITORING. This named SQL instance is displayed in the Backup Exec user interface as a recognized SQL instance.
However, until the Monitoring and Reporting feature of SBS 2003 is properly configured, the service associated with the SBSMONITORING named instance will be set to Disabled. This will cause an error when attempts are made to select the instance for backup.
We suggest you to either consult the Microsoft SBS 2003 documentation for instructions on configuring Monitoring and Reporting, and follow the steps provided, or do not select the SBSMONITORING instance for backup until it is configured properly.
Hope this resolves your issue and query.If the issue persists then kindly revert back with necessary information and error messages.