Sergey Kabashnyuk

If you have

28.11.2009 21:16:25 *ERROR* [Timer-2,JBoss-Cache-Cluster_db1tck_ws,127.0.0.1:7800] MPING: failed sending discovery request (MPING.java, line 346) 
java.io.IOException: Invalid argument
at java.net.PlainDatagramSocketImpl.send(Native Method)
at java.net.DatagramSocket.send(DatagramSocket.java:612)
at org.jgroups.protocols.MPING.sendMcastDiscoveryRequest(MPING.java:341)
at org.jgroups.protocols.PING.sendGetMembersRequest(PING.java:259)
at org.jgroups.protocols.Discovery$PingSenderTask$1.run(Discovery.java:407)
at java.util.concurrent.Executors$RunnableAdapter.
 

on Ubuntu 9.10 or over operation system  try to run you application with

-Djava.net.preferIPv4Stack=true

This happens because  JGroups does work with IPv6.