Invalid SQL virtual server name device interface=data domain

Hello, I am new for networker and trying to configure one of my test VM (2012 R2 std) which running sql server 2012 (using named instance). When I am executing backup from networker admin console its showing me following error:

29100:(pid 1136): Invalid SQL virtual server name device interface=data domain

38563:(pid 1136): Invalid option -a

37758:(pid 1136): Usage: nsrsqlsv [ ] {path}

options: [-CGjqRTvkuHXZ] [-s server] [-N name] [-b pool] [-g group]

         [-S count] [-l level] [-m masquerade] [-U user [-P passwd]]

         [[-a virtual-server] | [-c client]] [-f aes] [-w browse] [-y retention]

path:    d-path | i-path

d-path:  MSSQL: | [MSSQL:]s-path [[MSSQL:]s-path [...]]

i-path:  MSSQL$inst-name: | MSSQL$inst-name:s-path [...]

s-path:  database | database. | database.filegroup |

         database.filegroup. | database.filegroup.file

43709:(pid 1136):Stop time: Wed Nov 30 14:09:50 2016

Please guide me.

Regards