关于自动化ie的问题

问题： 关于自动化ie的问题
描述:

#include <windows.h>
      #define INITGUID
      #include <initguid.h>
      #include <exdisp.h>
      #include <memory.h>
#include <mshtml.h>
#include <iostream.h>
      HRESULT GetPostData(LPVARIANT pvPostData);
      void main()
      {
         HRESULT hr;
         IWebBrowser2* pWBApp = NULL; // Derived from IWebBrowser
 IHTMLDocument2* pHDoc = NULL;
 IHTMLBodyElement* pHBody = NULL;
         BSTR bstrURL = NULL, bstrHeaders = NULL;
   BSTR   bstrTitle;  
         VARIANT vFlags = {0},
            vTargetFrameName = {0},
            vPostData = {0},
            vHeaders = {0};
         if (FAILED(hr = CoInitialize(NULL)))
         {
            return;
         }
         if (FAILED(hr = CoCreateInstance(CLSID_InternetExplorer,
            NULL,
            CLSCTX_SERVER,
            IID_IWebBrowserApp,
            (LPVOID*)&pWBApp)))
         {
            goto Error;
         }
         bstrURL = SysAllocString(L"http://163.com");
         if (!bstrURL)
         {
            goto Error;
         }
         hr = pWBApp->Navigate(bstrURL, &vFlags,
                  &vTargetFrameName, &vPostData, &vHeaders);
         pWBApp->put_Visible(VARIANT_TRUE);
 hr = pWBApp->get_Document((IDispatch**)&pHDoc);
        if (!hr)
         {
cout <<GetLastError();
            goto Error;
         }
 hr =  pHDoc->get_title(&bstrTitle);
      Error:
         if (bstrURL) SysFreeString(bstrURL);
         if (bstrHeaders) SysFreeString(bstrHeaders);
         VariantClear(&vPostData);
         if (pWBApp) pWBApp->Release();
         CoUninitialize();
      }
哪位能帮我看看为什么  hr =  pHDoc->get_title(&bstrTitle);这句出错了.编译可以,执行的时候出错