“Robot inventory failed: Unable to open robotic path (201).”

The causes can be: (Reference: http://seer.entsupport.symantec.com/docs/269409.htm)

1. Because the library door is left open
2. The is library is not connected, offline, shutdown or in the middle of a scan
3. The library is not in SCSI mode
4. Some other software has locked the SCSI path (Like robtest)
5. SCSI path has changed.

Solutions:
1. Check that the library door is closed.
2. Check that the library is running, online and connected.
3. Check that the library is in SCSI mode.
4. Run: /usr/openv/netbackup/bin/bpps (UNIX) or <install_path>\veritas\netbackup\bin\bpps (windows)

Check that this command does not list any robtest/robtest.exe (UNIX/windows) process. If exists, kill the process

5. Open the Device Manager on windows and try to see if the “Medium Changer” is listed. It should exist for Netbackup to work.
6.  Run : /usr/openv/volmgr/bin/tpautoconf -r (UNIX) or <install_path>\veritas\volmgr\bin\tpautoconf -r (windows)

and try to see if robot is still communicating with the Operating System.
C:\Program Files\VERITAS\Volmgr\bin>tpautoconf -r
TPAC45 M4 DATA MagFile         3.05 RBD12A0007 2 0 0 0 Changer0 - -

7. If “tpautoconf -r” works, use the NetBackup Administration Console to re-browse for the robot on the Robot Control Host.

limit has been reached for requested resource NBU_POLICY.MAXJOBS.CatalogBackup

Most probably this is an issue about NBU 6.5.3. If you can look at the following bug report page:

http://seer.entsupport.symantec.com/docs/318079.htm

The easiest way to resolve the problem is to restart netbackup daemons.

Another method is explained in the above document.