Problem updating a large binary field (PostgreSQL, ODBC, VC++)

Hello,

I created a table where a record consists of a single field of type
lo. I'm trying to add a new record and store the contents of a file in
it. However, when I call CRecordset.Update() I get the following
exception: "SetPos with data_at_exec not yet supported". My table
doesn't get updated.

Environment: PostgreSQL 7.4.1 on Cygwin, Visual C++ .Net 2003, ODBC
driver 3.520. I pasted my code below (the line that causes the error
is marked). Anyone knows why it doesn't work, and if there's any other
way to do what I want?

TIA,
Pavel

CDatabase db;
CMyTable table(&db);
table.Open();
char* FileName          = "c:\\test.txt";
CFile f;
CByteArray ByteArray;

if (f.Open(FileName, CFile::modeRead, &e ))
{
  CByteArray ByteArray;
  long size = f.GetLength();
  ByteArray.SetSize(size); 
  BYTE *p = ByteArray.GetData(); 
  ZeroMemory(p, size); 
  long result = f.Read(p, size);

  table.AddNew();

  if(!(table.m_data.m_hData)) 
  { 
    ::GlobalFree(table.m_data.m_hData); 
    table.m_data.m_hData = GlobalAlloc(GMEM_MOVEABLE,size);
    if(table.m_data.m_hData) // GlobalAlloc could return NULL...
    {
        table.m_data.m_dwDataLength = size;
        LPVOID p2 = ::GlobalLock(table.m_data.m_hData);
        memcpy(p2, p, size);
        ::GlobalUnlock(table.m_data.m_hData);
        table.m_data.m_dwDataLength = ::GlobalSize(table.m_data.m_hData);

        // mark the record for the update
        table.SetFieldDirty(&(table.m_data), true);
        table.SetFieldNull(&(table.m_data), false);
    }
   else
   {
        AfxMessageBox("Couldn't allocate memory");
   }
}

table.Update(); // <-- THIS DOESN'T WORK!

---------------------------(end of broadcast)---------------------------
TIP 4: Don't 'kill -9' the postmaster