Now I'm back at the problem being on the Nook side of things. Managed to add a few music & video files to the library, (most of my file naming conventions break the scrappers) and am now able to play the file video and music files on my Ubuntu desktop after running the djmount script I'd found and mentioned above.
Its seems UPnP can only stream things that are referenced in the library.
Songs in the music library play on the Nook, the videos (rips of DVDs made from OTA recordings with a GoVideo DVD-Recorder box so the mpeg2 bitrates are modest, these types of files play on the Nook from the SD card) just give me a black screen in the nook media player and the XBMC UI gets sluggish until I quit the Nook player app, so my solution if any will now have to be found on the Nook side of things now that I've solved the part of the problem that was on the XBMC side.
I'd be very grateful if Ned Scott could explain how to make XBMC enable this: "XBMC now shares playlists, tags, even files not scanned into the library, all via UPnP. " as he mentioned in his reply. Renaming 3+TB of media files is not happening anytime soon, if ever!