如何使用接口IApplicationAssociationRegistration？

看下面的代码，头文件#include <shobjidl.h>,    IApplicationAssociationRegistration* pAAR;
HRESULT hr; hr = CoInitializeEx(0, COINIT_MULTITHREADED); hr = CoGetClassObject(CLSID_ApplicationAssociationRegistration, 
CLSCTX_INPROC, NULL, IID_IClassFactory, (void**)&pAAR);  if (FAILED(hr))
{
CoUninitialize();
return hr;
}

    hr = CoCreateInstance(CLSID_ApplicationAssociationRegistration,
                                  NULL,
                                  CLSCTX_INPROC,
                                  __uuidof(IApplicationAssociationRegistration),
                                  (void**)&pAAR);

hr = pAAR->QueryCurrentDefault(L"mail",AT_STARTMENUCLIENT, AL_EFFECTIVE,&name);
编译后总是报出 no GUID has been associated with this object！请问是什么原因啊？很急，在线等，马上结贴！