ich have the same problem:
two instances of jboss 3.2.3 on one machine (linux) one on port 1099 another on port 1101.
shutdown.sh -s localhost:1099 is ok
shutdown.sh -s localhost:1101 does nothing. there is no error-message. the command does not terminate.
i can stop both with "killall -9 java". if i want to stop just one thats no help.
i found the solution:
port 1101 was the rmi-port of jboss-service.xml. if i use the jndi-port 1102 it worked fine:
shutdown.sh -s localhost:1102