problem parsing a xml file with MSXML4 in C++

Here is my parsing code:

MSXML2::IXMLDOMNodePtr pNode = m_pXmlDoc->selectSingleNode(kNameOfChild.c_str());

MSXML2::IXMLDOMNodeListPtr pIDOMNodeList = NULL;
MSXML2::IXMLDOMNodePtr pIDOMNode = NULL;
long numOfChildNodes= 0;
BSTR bstrItemText;
HRESULT hr;

MSXML2::IXMLDOMElementPtr pChildNode = m_pXmlDoc->getElementsByTagName(kNameOfChild.c_str());


hr  = m_pXmlDoc->get_childNodes(&pIDOMNodeList);

hr = pIDOMNodeList->get_length(&numOfChildNodes);

And my xml file:

<?xml version="1.0"?>
<GovTalkMessage>
<EnvelopeVersion>1.0</EnvelopeVersion>
<Header>
  <MessageDetails>
     <Class>MOSWTSC2</Class>
     <Qualifier>acknowledgement</Qualifier>
     <Function>submit</Function>
     <TransactionID>20021202ABC</TransactionID>
     <CorrelationID>B07B9ED3176193DDC4EC39063848A927</CorrelationID>
     <ResponseEndPoint PollInterval="10">
      https://secure.gateway.gov.uk/poll
     </ResponseEndPoint>
     <GatewayTimestamp>2001-01-31T10:20:18.345</GatewayTimestamp>
  </MessageDetails>
  <SenderDetails/>
 </Header>
<GovTalkDetails>
   <Keys/>
</GovTalkDetails>
<Body/>
</GovTalkMessage>

• kNameOfchild is "Qualifier"
• pNode is always NULL
• pChildNode is always NULL
• hr returns S_OK
• numOfChildNodes is always 0

So, what am I doing wrong? Thanks

Try /GovTalkMessage/Header/MessageDetails/Qualifier for the XPath query.