[Cheaptrick]

Assuming that you already port forwarded the default BHD game port UDP 17479 (or a different game port that you like to use) on both your PC firewall (ex: Norton, McAfee, etc.), router firewall (ex: Netgear, D-Link, etc.) or to some extend your gateway modem frewall (depending on your internet provider) your game server will show up on the list of game servers running.

Hence it's not showing on the other PC within your network, I can say with absolute 100% certainty that the game port is blocked &/or not port forwarded on either your PC, router or gateway modem firewalls (if you used any).

You're hosting a game server on LAN, not Novaworld so the use of a Pinger doesn't apply here. It's a different story if you're hosting it on Novaworld as Nova made it difficult to login into game servers to combat game piracy. By that, you need to use a Pinger even if the host PC is inside your network. Not only that, you need to login & logout from time to time to Novaworld2's website in order for the Pinger to be able to ping a fresh list of game servers running. Also, even if you used a Pinger you can't just double click your game server & add it. You need to manually add the internal IP &/or localhost (127.0.0.1) to play if you're hosting a game server on Novaworld inside your network.