You should be able to use exact same settings as with previous version LW you used.

The thing about UPnP is it often listens through a different port each time it is used. Have you tried connecting with the OSX firewall turned off?

You are connecting via ethernet ... but there must be a connection device somewhere that the network connects to the internet. Are you connecting at home? What brand & model of modem/router is the network connected to the internet? Or is that Dash2?

The problem seems to be with the listening port being blocked. We need to find what it is that's blocking it.