When a command is run via the CLI, it has to run as a NetVault user. The environment variables NETVAULTCLIACCOUNT and NETVAULTCLIPASSWORD will let you configure this user and password. The problem with this is that the password is not secure. Anyone can recall the password from the NETVAULTCLIPASSWORD environment variable.
There is another way to configure the user and password however. The command nvpluginaccess can be run on the NetVault Backup server to configure the user and password that will be used. Although CLI is not a menu option in nvpluginaccess, you can use the "Specify plugin name" option to specify "CLI" or other plugins that are not listed.
This will permit the CLI command to be run but, if that command must use another plugin, it my require additional plugins to be configured. One example is the nvsetcreate command. If you use this to create a File System plugin, it will require also using nvpluginaccess for the "File System" plugin.