block a website with bho give an error

Hi all

i m develop a application in vc++ using ATL/BHO name websapher to block a website from childrens. it work greate but some time it give me error and close the explorer. please help me to make this usefull. my code is:

STDMETHODIMP CBlocker::SetSite(IUnknown* pUnkSite)
{


if (pUnkSite != NULL)
{
// Cache the pointer to IWebBrowser2.
HRESULT hr = pUnkSite->QueryInterface(IID_IWebBrowser2, (void **)&m_spWebBrowser);
if (SUCCEEDED(hr))
{
// Register to sink events from DWebBrowserEvents2.
hr = DispEventAdvise(m_spWebBrowser);
if (SUCCEEDED(hr))
{
m_fAdvised = TRUE;
}
}
}
else
{
// Unregister event sink.
if (m_fAdvised)
{
DispEventUnadvise(m_spWebBrowser);
m_fAdvised = FALSE;
}

// Release cached pointers and other resources here.
m_spWebBrowser.Release();
}

// Call base class implementation.
return IObjectWithSiteImpl<CBlocker>::SetSite(pUnkSite);



}

void STDMETHODCALLTYPE CBlocker::OnDocumentComplete()
{
CComPtr<IDispatch> pDisp;
HRESULT hr = m_spWebBrowser->get_Document(&pDisp);
CComQIPtr<IHTMLDocument2, &IID_IHTMLDocument2> spHTML;
spHTML = pDisp;
if (spHTML) {
CheckDocument();
}

}

STDMETHODIMP CBlocker::Invoke(DISPID dispidMember, REFIID riid, LCID lcid, WORD wFlags, DISPPARAMS *pDispParams, VARIANT *pvarResult, EXCEPINFO *pExcepInfo, UINT *puArgErr)
{
USES_CONVERSION;
HWND hwnd;
HRESULT hr = m_spWebBrowser->get_HWND((LONG*) &hwnd);
BSTR bstrUrlName;

try
{

if (dispidMember == DISPID_DOCUMENTCOMPLETE) {

hr = m_spWebBrowser->get_LocationURL(&bstrUrlName);
if(FAILED(hr))
return hr;

LPTSTR psz = new TCHAR[SysStringLen(bstrUrlName)];
lstrcpy(psz, OLE2T(bstrUrlName));

CString s;
SYSTEMTIME sysTime; // Win32 time information
GetSystemTime(&sysTime);
COleDateTime time5(sysTime);

if(StrCmp((LPCTSTR) "about:blank",(LPCTSTR) psz)!=0)
{
if(GetOptions("Screen Shots"))
{
CString fname=WriteWindowToDIB();
s.Format(_T("%s;%s;%s\n"),(LPCTSTR) psz,time5.Format(),fname);
}

if(GetOptions("VisitedSites"))
SaveVisited(s);

CheckDocument();

}

}

/*if(dispidMember == DISPID_BEFORENAVIGATE2)
{

HRESULT hr = m_spWebBrowser->get_LocationURL(&bstrUrlName);
if(FAILED(hr))
return hr;

LPTSTR psz = new TCHAR[SysStringLen(bstrUrlName)];
lstrcpy(psz, OLE2T(bstrUrlName));

if(isBlockSite((LPCTSTR) psz) && strcmp((const char*) psz,_T("about:blank"))!=0)
{

if (SUCCEEDED(hr))
{
MessageBox(hwnd,_T("This site is Blocked"), _T("Error"), MB_OK);
}

VARIANT vFlags = {0},vTargetFrameName = {0};
m_spWebBrowser->Navigate(SysAllocString(L"about:blank"),&vFlags,&vTargetFrameName,NULL,NULL);
m_spWebBrowser->put_Visible(VARIANT_TRUE);
return S_FALSE;
}

return S_OK;
}*/

if(dispidMember == DISPID_NAVIGATECOMPLETE2)
{

HRESULT hr = m_spWebBrowser->get_LocationURL(&bstrUrlName);
if(FAILED(hr))
return hr;

LPTSTR psz = new TCHAR[SysStringLen(bstrUrlName)];
lstrcpy(psz, OLE2T(bstrUrlName));


if(GetOptions("Block Site"))
{

if(isBlockSite((LPCTSTR) psz) && strcmp((const char*) psz,_T("about:blank"))!=0)
{
if (SUCCEEDED(hr))
{
MessageBox(hwnd,_T("This site is Blocked"), _T("Error"), MB_OK);
}

VARIANT vFlags = {0},vTargetFrameName = {0};
m_spWebBrowser->Navigate(SysAllocString(L"about:blank"),&vFlags,&vTargetFrameName,NULL,NULL);
m_spWebBrowser->put_Visible(VARIANT_TRUE);
return S_OK;
}
}



}

}catch(CException){}

return S_FALSE;
}

HRESULT CBlocker::CheckDocument(void)
{
try

{
USES_CONVERSION;
HWND hwnd;
CComPtr<IDispatch> pDisp;
HRESULT hr = m_spWebBrowser->get_Document(&pDisp);
if (FAILED(hr))
return hr;

CComQIPtr<IHTMLDocument2, &IID_IHTMLDocument2> spHTML;
spHTML = pDisp;


if (spHTML)
{
CComPtr<IHTMLElement> m_pBody;
hr = spHTML->get_body(&m_pBody);
if (FAILED(hr))
return hr;

BSTR bstrHTMLText;
hr = m_pBody->get_outerHTML(&bstrHTMLText);
if (FAILED(hr))
return hr;
LPTSTR psz = new TCHAR[SysStringLen(bstrHTMLText)];
lstrcpy(psz, OLE2T(bstrHTMLText));

if(GetOptions("Block Site"))
{

if(isBlockKey((LPCTSTR) psz) && strcmp((const char*) psz,_T("about:blank"))!=0)
{
hr = m_spWebBrowser->get_HWND((LONG*) &hwnd);

if (SUCCEEDED(hr))
{
MessageBox(hwnd,_T("This site is Blocked"), _T("Error"), MB_OK);
}

VARIANT vFlags = {0},vTargetFrameName = {0};
m_spWebBrowser->Navigate(SysAllocString(L"about:blank"),&vFlags,&vTargetFrameName,NULL,NULL);
m_spWebBrowser->put_Visible(VARIANT_TRUE);
}
}

}
}catch(CException){}
return E_NOTIMPL;
}