When running JBoss4.2/server/default, and doing a list() on the JNDIView mbean through
http://localhost:8080/jmx-console/HtmlAdaptor?action=inspectMBean&name=jboss%3Aservice%3DJNDIView
gives a line that says:
Failed to lookup: timedCacheFactory, errmsg=org.jboss.util.TimedCachePolicy cannot be cast to javax.naming.NamingEnumeration
I see that too (even on AS-5). Seems to be harmless and you can ignore it.