This is caused by a 2008 change to the Ubuntu/Debian Linux default network configuration. Essentially, the Java call InetAddress.getLocalHost(); always returns the loopback address, which is 127.0.0.1. Why? Because in these recent distros, a system call of $ hostname always returns an address mapped onto the loopback device, and this causes Ehcache's RMI peer creation logic to always assign the loopback address, which causes the error you are seeing. All you need to do is crack open the network config and make sure that the hostname of the machine returns a valid network address accessible by other peers on the network.

Some app servers do not permit the creation of message listeners. This issue has been reported on Websphere 5. Websphere 4 did allow it. Tomcat allows it. Glassfish Allows it. Jetty allows it. Usually there is a way to turn off strict support for EJB checks in your app server. See your vendor documentation.