When starting up JBoss 4.0.3, I get the JVM bind exception for port 1100.
This port is already taken by Symantec, so I imagine many people have this issue. (ccApp.exe)
I changed the following to a different port, recycled the server and it works fine.
In the file
server/default/deploy/cluster-service.xml
Change the port for the Mbean called
<mbean code="org.jboss.ha.jndi.HANamingService"
To something less commonly used like 1249