WinHelp in C++

Hello
I want to use WinHelp in a MFC application. I work with Visual Studio 2003.

I did already following:

// CUiApp Konstruktion
CUiApp::CUiApp()
{
  EnableHtmlHelp();
      // ZU ERLEDIGEN: Hier Code zur Konstruktion einfügen
      // Alle wichtigen Initialisierungen in InitInstance platzieren
}

When I call the Help, I call

  "ON_COMMAND(ID_HELP, CWinApp::OnHelp)"

the program jumps to apphelpx.cpp
void CWinApp::OnHelp()  // use context to derive help context
{
      if (m_dwPromptContext != 0)
      {
            // do not call WinHelp when the error is failing to lauch help
            if (m_dwPromptContext != ID_BASE_PROMPT+AFX_IDP_FAILED_TO_LAUNCH_HELP)
                  WinHelpInternal(m_dwPromptContext);
            return;
      }

      // otherwise, use CWnd::OnHelp implementation
      CWnd* pWnd = AfxGetMainWnd();
      ASSERT_VALID(pWnd);
      if (!pWnd->IsFrameWnd())
            pWnd->OnHelp();
      else
            ((CFrameWnd*)pWnd)->OnHelp();
}


at "pWnd->OnHelp();" the programm jumps to winfrmx.cpp
void CWnd::OnHelp()  // use context to derive help context
{
      // attempt to get help from whoever is tracking
      HWND hWnd = ::GetCapture();
      while (hWnd != NULL)
      {
            // attempt to process help
            if (::SendMessage(hWnd, WM_COMMANDHELP, 0, 0))
                  return;

            // check next parent/owner in the parent/owner chain
            hWnd = AfxGetParentOwner(hWnd);
      }
      // attempt to get help from whoever has the focus
      hWnd = ::GetFocus();
      while (hWnd != NULL)
      {
            // attempt to process help
            if (::SendMessage(hWnd, WM_COMMANDHELP, 0, 0))
                  return;

            // check next parent/owner in the parent/owner chain
            hWnd = AfxGetParentOwner(hWnd);
      }


when the program is at " if (::SendMessage(hWnd, WM_COMMANDHELP, 0, 0))" it opens an error window with the message "Failed to launch help."


What can I do??