Your issue is that, from description, you have issue on network layer where something is blocking the communication.  Few things to test:

- if you do nsrrpcinfo -p from client - does that work?

- if you do nsrrpcinfo -p from server - does that work?

- if any above fails, try same command from box itself (eg. nsrrpcinfo -p localhost from client and from server)

- In NW configuration, if using multihomed setup, make sure to define client with name over preferred network

- In NW configuration, if using multihomed setup, make sure to define client with backup server interface pointing towards preferred interface

- In NW server/media server configuration, make sure to use interface which is designed for data traffic