How to use the TAPI function lineInitializeEx?

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C++

Hello, everyone!
Now I am developing an application for Windows Mobile 6.1. I meet a problem about the function lineInitializeEx. I had written some code as below:

HLINEAPP hLineApp;
DWORD dwDevNum;
DWORD dwApiVersion = TAPI_CURRENT_VERSION;
LINEINITIALIZEEXPARAMS lineParams = {0};
lineParams.dwTotalSize = sizeof(LINEINITIALIZEEXPARAMS);
HANDLE hEvent = NULL;
HINSTANCE hInstance = AfxGetInstanceHandle();//::AfxGetApp()->m_hInstance;
LONG lResult = lineInitializeEx(&hLineApp,hInstance,NULL,NULL,
    &dwDevNum,&dwApiVersion,&lineParams);
if(lResult == 0)
{
    hEvent = lineParams.Handles.hEvent;
}

I find that the return value of lineInitializeEx is LINEERR_INVALPARAM. I had seek the answer on MSDN. It said that the specified hInstance parameter is invalid. Then I get the correct value for it using the code as above, and the code be set as comment. But the return is still wrong with those code. I think maybe some other parameters are wrong. I don't know how to fix it. I hope someone has experience can tell me. Thx! :)