Problem in Cimage

Hi,
I m trying to download and display image.My code works fine for some
time.After that i gives debug assertion error after CImage m_image;
 at line 504 ATLASSERT( hBitmap != NULL );,1572 ATLASSERT( nBytes ==
sizeof( BITMAP ) );,630ATLASSUME( m_hBitmap != NULL ); on
altimage.h.

I try to debug but unable to finderror. m_picturecontrol is picture
control from
http://www.codeproject.com/KB/graphics/CPictureControl.aspx?display=Print

void CScreenclientDlg::Downloadfile()
{
CString strHeaders = _T("Content-Type: image/gif");
    CInternetSession pSession;

    CString strQueryTemp, strQuery;
    //CString strResponse;
        strQueryTemp.LoadString(IDS_DOWNLOADFILE);
        strQuery.Format(strQueryTemp,accountno,sessid,sno);
        strQuery=L"http://www.mydomain.com/"+strQuery;

        pFile=pSession.OpenURL
(strQuery);//,NULL,INTERNET_FLAG_DONT_CACHE,NULL,NULL);
    if (pFile)
        {
            IStream* pStream;
            CImage m_image;

            if(CreateStreamOnHGlobal(NULL, TRUE, &pStream) == S_OK)
    {
        BYTE pBuffer[1024];
            UINT uiRead = 0;
ULONG ulWrittencount=0;

            while((uiRead = pFile->Read(pBuffer, sizeof(pBuffer))) != 0)
            {
                ULONG ulWritten = 0;
                pStream->Write(pBuffer, uiRead, &ulWritten);

            }

            lock=TRUE;

            HRESULT hr=m_image.Load(pStream);

{m_CtrlHeight=m_image.GetHeight();
m_CtrlWidth=m_image.GetWidth();
RedrawWindow();
}
m_picturecontrol.FreeData();

m_picturecontrol.SetWindowPos(NULL,0,0,m_image.GetWidth
(),m_image.GetHeight(),SWP_NOMOVE | SWP_NOZORDER);
    Invalidate();
RedrawWindow();

BOOL bResult= m_picturecontrol.Load(pStream);
pSession.Close();

m_image.Detach();
m_image.Destroy();
            lock=FALSE;
             }oldsno=sno;
        while(pStream->Release());

    }
delete pFile;

    }
    catch(CException *e)
        {

AfxBeginThread(threading, this);

        return;
        }

        AfxBeginThread(threading, this);

}
}

UINT CScreenclientDlg::threading1(LPVOID p)
{ CScreensharingclientDlg * me = (CScreensharingclientDlg *)p;

     me->showimage(me->count);

     return 0 ;
}

I works fine for some time but once i got error its repeat again and
again.Even when i dbug program agin immediately.
I am unable to understand reason.Is am i missing deallocating any
resource or pointer
Please help its urgent