getNNode() NullPointException!!!

[jametang]

java.lang.NullPointerException
Attempt to invoke virtual method 'int org.cybergarage.xml.Node.getNNodes()' on a null object reference

org.cybergarage.upnp.event.NotifyRequest.getPropertyList(NotifyRequest.java:191)
org.cybergarage.upnp.ControlPoint.httpRequestRecieved(ControlPoint.java:577)
org.cybergarage.http.HTTPServer.performRequestListener(HTTPServer.java:212)
org.cybergarage.http.HTTPServerThread.run(HTTPServerThread.java:48)

Should I setXMLParser() in anywhere ?