Uvazhaemie Gospoda!
Pomogite razobrat'sya s problemoi:
Ya sozdau s pomosh'u ATL elementarnij COMponent s dvumya funkciyami:

[id(1), helpstring("method ReadFromFile")] HRESULT ReadFromFile([in] BSTR fName, [out, retval] BSTR *txtRet);
[id(2), helpstring("method Save2File")] HRESULT Save2File([in] BSTR fName, [in] BSTR txt2save);

V funkcii ReadFromFile ya prosto chitau text iz faila i vozvrashau ego.
I poluchau — error : Memory couldn't be 'written'
hotya tot zhe kod v obichnoi programme (ne v COM) rabotaet bezukoriznenno, edinstvennoe otlichie preobrazovanie iz char* v BSTR.

Esli uvazhaemie specialisti smogut vzglyanut' na privedennii nizhe code i ukazat' mne na oshibku budu priznatelen :-).

STDMETHODIMP CFIO::ReadFromFile(BSTR fName, BSTR *txtRet)
{
    // TODO: Add your implementation code here
    USES_CONVERSION;
    _bstr_t bstrFName(fName,FALSE);
    HANDLE hFile;
    DWORD dwFileSize;
    DWORD dwBytesRead;
    BOOL bResult;
    char *pBuf;

    hFile = CreateFile(bstrFName,GENERIC_READ,FILE_SHARE_READ,NULL,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL, NULL);
    if (hFile == INVALID_HANDLE_VALUE) 
    {
        CloseHandle(hFile);
        return E_FAIL;
    }
    dwFileSize = GetFileSize(hFile,NULL);
    dwBytesRead = 0;
    if (dwFileSize == INVALID_FILE_SIZE)
    {
        CloseHandle(hFile); 
        return E_FAIL;
    } 
    pBuf = new char[dwFileSize];
    bResult = ReadFile(hFile,pBuf,dwFileSize,&dwBytesRead,NULL);
    if (bResult==0)
    {
        CloseHandle(hFile); 
        return E_FAIL;
    } 

    *txtRet = ::SysAllocString(A2OLE(pBuf));
//    delete pBuf;
    CloseHandle(hFile); 
    return S_OK;
}

P.S.
proshu prosheniya za translit, poka u menya net drugoi vozmozhnosti beglo pisat' po russki