If multicast is not properly configured.. we run the chance of filling the logs with error messages on a vanila install. We now gard against this by only reporting the error mesasge the first time we hit the error. We keep trying to do mutlicast advertising, but suppress futher error messages.
incubator/activemq/trunk/activemq-core/src/main/java/org/apache/activemq/transport/discovery/multicast/MulticastDiscoveryAgent.java