I'm not sure that this could be helpful though...
Check your /etc/hosts and make sure that 127.0.0.1 has localhost and <real IP address> get some <human readable name> like following. (at every node)
172.16.100.100 jboss1 jboss1.mydomain.com
If it still dosen't work
try allmulti set to your network interface.
ifconfig eth0 allmulti
Please let us know, if one of above solves your problem.
Is your box multi-homed ? If so, use UDP(bind_addr=XXX) and define XXX to be your eth0 device.