I met SoapFault. why this fault is generated?

org.apache.muse.ws.addressing.soap.SoapFault: NAMESPACE_ERR: An attempt is made to create or change an object in a way which is incorrect with regard to namespaces.


------------------------error generating code----------------------------------
 public synchronized Element getResourceProperty(int flag, String resvID, QName propertyqname){
                 
              Document doc = XmlUtils.createDocument();
         Element root =  XmlUtils.createElement(doc, gnrmConstants.GET_PROPERTY_RESPONSE_QNAME);
         doc.appendChild(root);

         Vector<String> result = new Vector<String>();
                 
         String propertyname = propertyqname.getLocalPart();
         System.out.println("prpertyname : " + propertyname );
                 
         result = grrManager.QueryResourceResvStatus(flag, resvID, propertyname);
                 
         Element resultChild = XmlUtils.createElement(propertyqname, "test get");
 
             // --> error code
             Element value = (Element)doc.importNode(resultChild, false);
 
        root.appendChild(value);

         return root;
 }
 
help me, all