A DLNA server serves up media files. If Netflix allowed you to download its content, like you can download iPlayer content, then the DLNA server on your PC might be able to make the files containing the downloaded content available to the DLNA client on your Humax box. But Netflix doesn’t (allow downloads).
The easiest way to watch your PC Netflix streams on your TV would probably be to connect the PC to the TV by cable. Or buy Chromecast or Roku or similar.