How to Connect SampleGrabber and SamrtTee ?

Hello ,everybody! I wanna the two filters work together. But there is a error .My source code is below:

IPin * pGrabberOut = GetSampleGrabberOutPutPin() ;
IPin * pIn = GetSmartTeeInPutPin();
hr = pGraph->Connect(pGrabberOut,pIn);

GetSampleGrabberOutPutPin()
{
if(pBuild)
{
IPin * pPin;
HRESULT hr = pBuild->FindPin(pSampleGrabber,PINDIR_OUTPUT,NULL,NULL,FALSE,0,&pPin);
if(SUCCEEDED(hr))
{
pPin->Release();
return pPin;
}
}
return NULL;
}

GetSmartTeeInPutPin()
{
if(pSmartTee)
{
IPin * pPin;
HRESULT hr = pSmartTee->FindPin(L"Input",&pPin);
if(SUCCEEDED(hr))
{
pPin->Release();
return pPin;
}
}
return NULL;
}

but the return value(hr) is VFW_E_CANNOT_CONNECT. Guys,please help me.