From the Admin Guides (in this case the Oracle Database Agent):
"...
A database backup requires an Application Backup schedule. You cannot perform backups if this type of schedule is not included in the policy. The database agent automatically creates this schedule, named Default-Application-Backup, when you configure a new database policy. To configure an Application Backup schedule
1 In the Policy dialog box, click the Schedules tab. To access the Policy dialog box, double-click the policy name in the Policies list in the NetBackup administration console.
2 Double-click the schedule that is named Default-Application-Backup.
3 Specify the other properties for the schedule.
..."
and
"...
The Application Backup schedule enables user-controlled NetBackup operations from the client. These operations include those initiated from the client and those initiated by an automatic schedule on the master server. NetBackup uses the Application Backup schedule when the user starts a backup manually. Configure at least one Application Backup schedule for each database policy. The Default-Application-Backup schedule is configured automatically as an Application Backup schedule.
..."
So, it seems like you
need an Application Backup to allow for backups to take place. To ensure this the agent creates one by default, you can then change this as required. That's my take on it anyway...
***EDIT***
Additionally (also cribbed from the Admin Guide):
"...
Schedules determine when NetBackup for Oracle initiates a backup. An Oracle backup requires at least two different schedules:
■ An Application Backup schedule. When you create an Oracle policy,
NetBackup for Oracle
automatically creates a Default-Application-Backup
schedule.
■ An Automatic Full Backup schedule.
You create this schedule. It enables scheduled backup operations on the client.
..."
which basically states the same thing!!
