Local html (RoboHelp) index online help file under MFC is not opened - c++

Question

I followed all the instructions that is referred here :
http://help.adobe.com/en_US/robohelp/robohtml/WS5b3ccc516d4fbf351e63e3d11aff59c571-7f43.html
My CMainFrame::HtmlHelp overiden handler looks like this :
void CMainFrame::HtmlHelp(DWORD_PTR dwData, UINT nCmd)
{
// TODO: Add your specialized code here and/or call the base class
CWaitCursor wait;
// Get the path to the Help system
CWinApp* pApp = AfxGetApp();
ASSERT_VALID(pApp);
// Set the path to server-based help
CString csOnlineHelpPath = _T("C:\\Help\\Final\\index.htm");
PrepareForHelp();
// must use top level parent (for the case where m_hWnd is in DLL)
CWnd* pWnd = GetTopLevelParent();
// finally, run the RoboHelp Help engine
if (!RH_ShowHelp(pWnd->m_hWnd, csOnlineHelpPath, nCmd, dwData))
AfxMessageBox(AFX_IDP_FAILED_TO_LAUNCH_HELP);
}
The problem is that the help is never opened. I tried to debug the RoboHelp_CSH.cpp file and I found out that at the line #3267 with the code
MultiByteToWideChar(CP_ACP, MB_USEGLYPHCHARS, szTempFile, (int)uLen, bstr, uLen+1);
the bstr buffer have an extra char at the end that makes the following code
hr=s_pstBrowser->Navigate(bstr, &vFlags, &vTargetFrameName, &vPostData, &vHeaders);
HWND hWnd;
hr=s_pstBrowser->get_HWND((long*)&hWnd);
if (SUCCEEDED(hr))
{
::SetForegroundWindow(hWnd);
}
::SysFreeString(bstr);
}
to fail. The original szTempFile has the data below
C:\Users\sdancer\AppData\Local\Temp\robohelp_csh.htm
and the bstr the the following (the DC2 is the symbol I show inside notepad++, unside VS2008 I see an up and down arrow).
C:\Users\sdancer\AppData\Local\Temp\robohelp_csh.htmDC2
What am I doing wrong here ?