求助~用sqlquery往数据库插入二进制出现内存错误

function TServerMethods1.UploadPic(uName: string; uPortrait: TStream): Boolean;

//上传图片

const

  BufSize = 51200;

var

  Stream: TStream;

  MS: TMemoryStream;

  Buffer: TBytes;

  ReadCount: Integer;

begin

  Result := False;

  Stream := uPortrait;

  try

    MS := TMemoryStream.Create;

    if Stream.Size < -1 then

    begin

      SetLength(Buffer, BufSize);

      repeat

        ReadCount := Stream.Read(Buffer[0], BufSize);

        if ReadCount > 0 then

          MS.Write(Buffer[0], ReadCount);

      until ReadCount < BufSize;

    end

    else

      MS.CopyFrom(Stream, 0);

      MS.Position := 0;

      MS.SaveToFile('c:\users\fky\desktop\123.bmp');

     // 上面的都ok

    try

      with sqlqry_Pic do

      begin

        Close;

        SQL.Clear;

        SQL.Add('update t_User set u_Portrait = :p_Portrait where u_Name = :p_Name');

        TBlobField(Params.ParamByName('p_Portrait')).LoadFromStream(MS);

       //  就是到上面这行,出现内存错误了

        Params.ParamByName('p_Name').Value := uName;

        ExecSQL(False);

        Result := True;

      end;

    except

      Result := False;

    end;

  finally

    MS.Free;

  end;

end;