编写word插件，任务窗对象spCustomTaskpane总是创建失败，为什么呢，求救！

Question

STDMETHODIMP CConnect::raw_CTPFactoryAvailable(struct ICTPFactory * CTPFactoryInst )
{
CComPtr<Office::_CustomTaskPane>spCustomTaskpane;
    spCustomTaskpane=NULL;

HRESULT hr = CTPFactoryInst->raw_CreateCTP(_com_util::ConvertStringToBSTR("SampleActiveX.myControl"),
 _com_util::ConvertStringToBSTR("Task Pane Example"),\
                       vtMissing,&spCustomTaskpane);
spCustomTaskpane->PutVisible(true);
return S_OK;   
}spCustomTaskpane总是创建失败，望各位大侠帮忙分析分析，在线急等