[JuanOrtega]

Hola tengo el siguiente codigo :

Código Delphi [-]
unit tool;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants,
  System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.ComCtrls, IdBaseComponent,
  IdComponent, IdTCPConnection, IdTCPClient, IdHTTP, Vcl.StdCtrls, IdSSLOpenSSL,
  IdIOHandler, IdIOHandlerSocket, IdIOHandlerStack, IdSSL, uLkJSON;

type
  TForm1 = class(TForm)
    StatusBar1: TStatusBar;
    PageControl1: TPageControl;
    TabSheet1: TTabSheet;
    TabSheet2: TTabSheet;
    nave: TIdHTTP;
    TabSheet3: TTabSheet;
    TabSheet4: TTabSheet;
    GroupBox1: TGroupBox;
    ip: TEdit;
    Button1: TButton;
    GroupBox2: TGroupBox;
    console1: TMemo;
    ssl: TIdSSLIOHandlerSocketOpenSSL;
    procedure Button1Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  api_key: string;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
  api_key := 'test';
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  code: string;

var
  json, json2: TlkJSONobject;
  i: integer;

var
  ip_found, country_found, country_code, region_name, postal_code: string;

var
  ip_str, product, version, data, cpe, timestamp, last_update, port, os, isp,
    ans, banner: string;

begin
  code := nave.Get('https://api.shodan.io/shodan/host/' + ip.Text + '?key='
    + api_key);

  json := TlkJSON.ParseText(code) as TlkJSONobject;

  for i := 0 to json.Field['data'].Count - 1 do
  begin
    console1.Lines.Add('------------------------------------');
    json2 := (json.Field['data'].Child[i] as TlkJSONobject);

    try
      begin
        console1.Lines.Add(json.Field['ip_strz'].SelfTypeName);
      end;
    except
      //
    end;

  end;
end;

end.

El problema es que estoy tratando de verificar si un field existe por ejemplo ip_strz , en el control uso SeldTypeName para ver si es null y asi darme cuenta pero siempre me da error , trate usando try y except pero sigue dando error , el error que siempre da es este :

Acess violation at adress in module 'shodan.exe' , read of address 000000

¿ Alguien me puede ayudar ?