Just got this one again.
snert:/im/rhq/modules/enterprise/agent/target/rhq-agent hrupp$ bin/rhq-agent.shListening for transport dt_socket at address: 8788 RHQ 4.4.0-SNAPSHOT [74326f0] (null) The server has rejected the agent registration request. Cause: [org.rhq.core.clientapi.server.core.AgentRegistrationException:An agent is trying to register with an existing agent name [snert] without providing a valid security token. If you are attempting to re-register this agent, please consult an administrator to reconfigure this agent with its proper security token.] Will retry the agent registration request soon...
Neither this, nor rhq-agent.sh --help tells me the magic -Dx=y combination to pass the token in - I think this is not user friendly.