The problem that causes this error is that BackupExec uses Windows cached credentials instead of the Service credentials used by the NSS6000 and therefore you cannot add a Backup-to-Disk folder when you use the administrator and password from the NSS6000.
Now to solve this problem:
1) Disconnect all drive mappings in Windows to your NSS6000 and close any other connections related to the NSS6000. 2) Logout of Windows and log back in (this is to clear the cached credentials) 3) Open Windows Explorer and choose "Map Network Drive". 4) Enter the path to the shared folder (\\NSS6000DeviceName\SharedFolderName) on the NSS6000 and choose any free Drive letter. 5) Choose "Reconnect at logon". DO NOT Choose "Connect using a different user name"!!! 6) Hit OK. After this you will be prompted to enter credentials. If you are not prompted you still have an open connection to the NSS and you will have to start back at step 1. 7) Enter the DeviceName\UserName and the Password for the user account on the NSS6000 in the prompted box. Check the box to remember the password. 8) After the NSS6000 opens in Explorer you can open BackupExec and add all your Backup-to-Disk folders.
That should resolve your issue with Symantec BackupExec and the error message of being unable to create a backup folder.
