视频连接，调用CoCreateInstance，Win7报故障,xp正常

视频会议系统，调用CoCreateInstance，Win7报故障,xp正常。故障代码是  1008。
Win7 下注册了rtcdll.dll，好象也没用HRESULT CAVDConfDlg::InitRTCClient()
{
HRESULT hr;
m_pClient = NULL;
m_pEvents = NULL;

hr = CoInitialize(NULL);
if (FAILED(hr))
{
return hr;
}
hr = CoCreateInstance (CLSID_RTCClient, NULL,
CLSCTX_INPROC_SERVER, IID_IRTCClient,
(LPVOID *)&m_pClient);
if (FAILED(hr))                     /*故障之处，Win7下此处报故*/
{
return hr;
}
hr = m_pClient->Initialize();
if (FAILED(hr))
{
SAFE_RELEASE(m_pClient);
return hr;
}
m_pClient->SetPreferredMediaTypes ( RTCMT_ALL, VARIANT_TRUE );
long lEventMask = RTCEF_SESSION_STATE_CHANGE |
  RTCEF_MESSAGING |
  RTCEF_MEDIA |
  RTCEF_INTENSITY |
  RTCEF_CLIENT;
hr = m_pClient->put_EventFilter( lEventMask );
    if ( FAILED(hr) )
    {
        SAFE_RELEASE(m_pClient);
        return hr;
    }
    m_pEvents = new CRTCEvents;
    if (!m_pEvents)
    {
        SAFE_RELEASE(m_pClient);
        return hr;
    }
    hr = m_pEvents->Advise( m_pClient, m_hWnd );
    if ( FAILED(hr) )
    {
        SAFE_RELEASE(m_pClient);
        return hr;
    }
    
    hr = m_pClient->put_ListenForIncomingSessions(RTCLM_BOTH); 

    if ( FAILED(hr) )
    {
    
        SAFE_RELEASE(m_pClient);
        return hr;
    }

if (m_AVDlg)
m_AVDlg.SetState (RTCSS_IDLE);
return S_OK;
}