help about vc alt webservice

[discoverx]

hi,everyone.
i create a vc atl console app that consume a c# implemented .asmx
webservices ,and this is the
client vc++ code:
#include "stdafx.h"
#include "documentproxy.h" //web services proxy stub header
using namespace Document;

int _tmain(int argc, _TCHAR* argv[])
{
CoInitialize(NULL);
{
HRESULT hr;
CDocumentT<CSoapWininetClient> srv;
LPCTSTR szUrl = TEXT("<some web services end point url.asmx>");
srv.SetUrl(szUrl);
srv.SetTimeout(2000);
BSTR szRet;
HRESULT hRet=NULL;
hRet=srv.HelloWorld(&szRet);
if( SUCCEEDED(hRet))
{
printf("Result %S\n", szRet);
::SysFreeString( szRet);
}
srv.Cleanup();
}
CoUninitialize();
return 0;
}

everytime when i execute the code,i get a error as :
runtime error R6025
- pure virtual function call

my environment is vs.net 2003 with .net framework 1.1 and OS winxp sp2.
can anyone help me? thanks!