To quell these errors, the following lines have to be added to the run.conf:
# stuff for JMX
JAVA_OPTS="$JAVA_OPTS -Dcom.sun.management.jmxremote.port=6789"
JAVA_OPTS="$JAVA_OPTS -Dcom.sun.management.jmxremote.ssl=false"
JAVA_OPTS="$JAVA_OPTS -Dcom.sun.management.jmxremote.authenticate=false"
JAVA_OPTS="$JAVA_OPTS -Djava.rmi.server.hostname=your.jboss.ip.address"
JAVA_OPTS="$JAVA_OPTS -Djboss.platform.mbeanserver"
JAVA_OPTS="$JAVA_OPTS -Djavax.management.builder.initial=org.jboss.system.server.jmx.MBeanServerBuilderImpl"
# there's an interaction between JDK 6 and JBoss LogManager when JMX is turned on..
JAVA_OPTS="$JAVA_OPTS -Djava.util.logging.manager=org.jboss.logmanager.LogManager"
JAVA_OPTS="$JAVA_OPTS -Dorg.jboss.logging.Logger.pluginClass=org.jboss.logging.logmanager.LoggerPluginImpl"
JBOSS_CLASSPATH="$JBOSS_CLASSPATH:/home/orly/sw/jboss-6.0.0.Final/lib/jboss-logmanager.jar"
Note that the above example turns off all authentication for JMX connections.. not something you'd want to do on a server that's on a public IP. But I am lazy.. in any case, if you're using Linux, you can use IPTables to restrict which IP's can connect to your JMX port.