This Knowledgebase article provides information about the SharePoint 2003 SP2 Backup/Restore feature failing to restore a previously taken backup when Neverfail Heartbeat is running.
With Neverfail for SharePoint installed and running, when attempting to restore a backup that was previously taken using the SharePoint 2003 SP2 Backup Restore feature, the restore fails.
Restoring SharePoint from a backup requires exclusive access to the SQL Server database which is not possible while Neverfail for SQL Server is monitoring the database.
During restore operations with SharePoint 2003 SP2 Backup/Restore features, Neverfail Heartbeat's application monitoring should be turned off by placing the system into Maintenance mode. Alternatively, Neverfail Heartbeat can be shutdown. When restore operation is complete, Maintenance Mode can be turned off.
Neverfail for SharePoint All Versions
SharePoint 2003 SP2