请教一个数据库问题(vc+ado access)?

向数据库里添加字段：
sql_.Format("SELECT* FROM STUDENT WHERE CODE ISNULL");
    _bstr_t sql=sql_;
    _variant_t vNull;
    vNull.vt=VT_ERROR;
    vNull.scode=DISP_E_PARAMNOTFOUND;
    try
    {
    hr=pRset.CreateInstance(__uuidof(Recordset));
    if(SUCCEEDED(hr))
    {
        pRset->PutRefActiveConnection(pConn);
        hr=pRset->Open(_variant_t(sql),vNull,adOpenKeyset,adLockOptimistic,adCmdText);
            if(SUCCEEDED(hr))
    {
      COleSafeArray vaFieldlist;
      vaFieldlist.CreateOneDim(VT_VARIANT,3);
     long lArrayIndex[1];
   lArrayIndex[0]=0;
vaFieldlist.PutElement(lArrayIndex,&(_bstr_t("name")));
lArrayIndex[0]=1;
vaFieldlist.PutElement(lArrayIndex,&(_bstr_t("code")));
lArrayIndex[0]=2;
vaFieldlist.PutElement(lArrayIndex,&(_bstr_t("telno")));
COleSafeArray vaValuelist;  
lArrayIndex[0]=0;
vaValuelist.PutElement(lArrayIndex,&(_variant_t("m_name")));
lArrayIndex[0]=1;
vaValuelist.PutElement(lArrayIndex,&(_variant_t("m_code")));
lArrayIndex[0]=2;
vaValuelist.PutElement(lArrayIndex,&(_variant_t("m_telno")));
pRset->AddNew(vaFieldlist,vaValuelist);
pRset->Update();     //m_name,m_code,m_telno为编辑框变量，为CString类型；
RefreshData();//刷新list Control 里的内容。
pRset->Close();
}
else{AfxMessageBox("失败1");}
}
else{AfxMessageBox("失败2");}}
    catch(_com_error&e)
    {
      AfxMessageBox(e.ErrorMessage());
    }运行后，提示错误信息：IDispatch error #3092
msdn 里的解释为：There is no account for this computer in the security database.
请问这怎么解决。