If you're running the commview tool on your same computer, I guess the packets are on your network (though I wouldn't have expected them to be).
Is there any way to associate a 239.x.x.x address with your computer (as well as your current ip address) so that you are 'entitled' to the messages?
If not, I vaguely recall a mode for a connection or card that allowed it to 'see' network packets that were not addressed to it. (If commview is seeing the 239 broadcasts I think that's how it works), but I'm not aware of how to put it in that mode.
I remembered the name 'promiscuous mode' for this type of connection. Looking it up as a definition I find:
http://en.wikipedia.org/wiki/Promiscuous_mode