MSXML: troubles with "insertBefore" in Microsoft Visual C++

Hi Gurus!

I have the simplest xml document (bool.xml):
<?xml version="1.0"?>
<Report>
...
</Report>

I've written the small program (inserting XSL reference in the prolog):

Dim xmlDoc,pi,ref
set xmlDoc = CreateObject ("Msxml.DOMDocument")
xmlDoc.async = false
xmlDoc.resolveExternals = false
xmlDoc.load ("d:\\book.xml")
ref="type=""text/xsl"" href=""mysheet.xsl"""
set pi = xmlDoc.createProcessingInstruction("xml-stylesheet",ref)
xmlDoc.insertBefore pi,xmlDoc.childNodes.item(1)
WScript.Echo(xmlDoc.xml)

It works fine!

Next, I tried to do the same using Microsoft Visual C++:


IXMLDOMDocumentPtr XmlDocPtr;
_bstr_t bstrXMLReport(_T("d:\\book.xml");
VARIANT_BOOL vtResult;
HRESULT hr = XmlDocPtr.CreateInstance(MSXML::CLSID_DOMDocument) ;

if (FAILED(hr))
{
AfxMessageBox("Failed to CreateInstance(CLSID_DOMDocument)");
return;
};

XmlDocPtr->async=FALSE;
XmlDocPtr->resolveExternals=FALSE;

vtResult=XmlDocPtr->load(bstrXMLReport);
if (vtResult == VARIANT_FALSE)
{
AfxMessageBox("Failed to load XML document");
return;
};

IXMLDOMProcessingInstructionPtr pi;
_bstr_t bstrTarget(_T("xml-stylesheet"));
_bstr_t bstrData(_T("type=\"text/xsl\" href=\"mysheet.xsl\""));
pi=XmlDocPtr->createProcessingInstruction(bstrTarget,bstrData);
BSTR qqq;
pi->get_xml(&qqq);

CComVariant varRef;
IXMLDOMNodePtr pFirst,pXMLNodeCur;
XmlDocPtr->childNodes->get_item(1,&pFirst);
varRef=pFirst;

try
{
XmlDocPtr->insertBefore(pi,t);
AfxMessageBox(XmlDocPtr->xml);
}
catch(_com_error &er)
{
TCHAR szErr[MAX_PATH];
memset(szErr,0,sizeof(szErr));
_tcscpy(szErr,(LPCTSTR)er.Description());
AfxMessageBox(szErr);
};


After that, I've got the exception "The parameter is incorrect."
Why? I suspect the incorrect usage of insertBefore method.


What should I do?