JON Agent auto-update fails

Issue

• Attempt to start JBoss ON agent fails:

  C:\rhq-agent\bin>rhq-agent.bat 
  RHQ 3.0.0.GA [8fb6059] (Wed Jul 28 21:17:44 CEST 2010)
  This version of the agent is not supported by the server - an agent update must be applied
  The agent update thread has started - will begin the agent auto-update now!
  The agent will wait for [2] threads to die
  This version of the agent is not supported by the server - an agent update must be applied
  This version of the agent is not supported by the server - an agent update must be applied
  Exception in thread "RHQ Agent Registration Thread" java.lang.IllegalStateException: The agent is already in the process of updating itself
          at org.rhq.enterprise.agent.AgentUpdateThread.lock(AgentUpdateThread.java:261)
          at org.rhq.enterprise.agent.AgentUpdateThread.updateAgentNow(AgentUpdateThread.java:77)
          at org.rhq.enterprise.agent.AgentMain$1.run(AgentMain.java:1376)
          at java.lang.Thread.run(Thread.java:619)
  This version of the agent is not supported by the server - an agent update must be applied
  Failed to start the agent org.rhq.core.clientapi.server.core.AgentNotSupportedException
          at org.rhq.enterprise.agent.AgentMain.waitForServer(AgentMain.java:1528)
          at org.rhq.enterprise.agent.AgentMain.start(AgentMain.java:639)
          at org.rhq.enterprise.agent.AgentMain.main(AgentMain.java:413)
  Downloaded the agent update binary to [C:\rhq-enterprise-agent-4.4.0.JON311G A.jar]
  Will use the Java executable [C:\JDK_1.6\bin\java.exe]
  Now executing agent update - if all goes well, this is the last you will hear of this agent: 
  [ProcessExecution: executable=[C:\PRG\JDK_1.6\bin\java.exe], args=[[-jar, C:\rhq-enterprise-agent-4.4.0.JON311GA.jar, --pause=20000, --update=C:\rhq-agent]], env-vars=[null], working-dir=[C:\], wait=[0], capture-output=[false], kill-on-timeout=[false], executable-is-command=[true]]