Please try to update the hosts files of the master and media server with the respective IP address and hostnames.
If that is already in place you can check this technote.
http://www.symantec.com/docs/TECH46050
Thanks
Ashish
If you run the incremental backup in this case it will run as a full backup. And during the next attempt when this incremental backup runs it will backup only the changes.
Thanks
Ashish
Just to get a better clarity could you please elaborate more and let us know if the backup jobs are running for your clients or else the netbackup services are not running in this case.
In addition to the above comments you can also refer to the Best Practice guide for SLP.
http://www.symantec.com/business/support/index?page=content&id=TECH153154
Regards,
Ashish