I've been having problems with an xPL install on one of our laptops. It has both ethernet and wireless networking, with one shutting off when the other is active. There is an xPL network setting, specifying which addresses to listen to for xPL messages. (It can be set using xPLHAL.) By default, it is configured to use "ALL" interfaces, but for whatever reason it is not working on my laptop. I changed the Listen To setting to the ethernet IP address (which is what it's connected to the most), and voila - we have xPL working! However, I can't use xPL wirelessly unless I change the Listen To address. Sounds like that'd be a good xPL app to switch that when networking changes - at least until that's fixed with the hub. Still, the xPL hub needs to be restarted when you change network adapters. That's not very convenient.
I have a feeling this will resolve the problem I was having with xPL dying after installing the bluetooth adapter on another machine. The bluetooth adapter also creates a network device and is probably confusing xPL the same way the wireless adapter was.