delphi 2010 - tidhttp post

Question

i want to post data to the following url:

http://mehratin.heroku.com/personals/new

i write the following code but has problem:

procedure TForm1.Button3Click(Sender: TObject);
var
  aStream: TMemoryStream;
  Params: TStringList;
begin
  aStream := TMemoryStream.Create;
  Params := TStringList.Create;
  try
    with IdHTTP1 do
    begin
      Params.Add('fname=123');
      Params.Add('lname=123');
      Request.ContentType := 'application/x-www-form-urlencoded';
      try
        Response.KeepAlive := False;
        Post('http://localhost:3000/personals/new', Params);
      except
        on E: Exception do
          showmessage('Error encountered during POST: ' + E.Message);
      end;
    end;

how can i post data by TIDHtttp.post method in delphi 2010?