During AS5 boot we get this exception when using JBossWS-Metro:

javax.management.InstanceAlreadyExistsException:
jboss.deployment:id="vfszip:/opt/svn/jbossas/trunk/build/output/jboss-5.0.0.GA/server/default/deployers/jbossws.deployer/jaxb-xjc.jar/1.0/",type=SubDeployment already registered.
at org.jboss.mx.server.registry.BasicMBeanRegistry.add(BasicMBeanRegistry.java:767)
at org.jboss.mx.server.registry.BasicMBeanRegistry.registerMBean(BasicMBeanRegistry.java:236)
at sun.reflect.GeneratedMethodAccessor74.invoke(Unknown Source
...

this is due to the way the jaxb-xcj.jar artifact is packaged.

See http://www.jboss.com/index.html?module=bb&op=viewtopic&t=143588 where Ales suggests how to deal with this.