В чем может быть ошибка

unit Unit1;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ExtCtrls, jpeg;
 
type
  TForm1 = class(TForm)
    GroupBox1: TGroupBox;
    GroupBox2: TGroupBox;
    RadioButton1: TRadioButton;
    RadioButton2: TRadioButton;
    RadioButton3: TRadioButton;
    RadioButton4: TRadioButton;
    RadioButton5: TRadioButton;
    RadioButton6: TRadioButton;
    ComboBox1: TComboBox;
    Image1: TImage;
    ListBox1: TListBox;
    ListBox2: TListBox;
    procedure RadioButton1Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure ComboBox1Change(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
 
var
  Form1: TForm1;
 
implementation
 
{$R *.dfm}
 
procedure TForm1.RadioButton1Click(Sender: TObject);
var i: Integer;
begin
ComboBox1.Clear;
ComboBox1.Tag := (Sender as TRadioButton).Tag;
for i := 0 to 5 do
ComboBox1.Items.Add (ListBox1.Items [ComboBox1.Tag + i]);
ComboBox1.ItemIndex := 0;
Image1.Picture.LoadFromFile (ListBox2.Items [ComboBox1.Tag]);
end;
 
procedure TForm1.FormCreate(Sender: TObject);
begin
RadioButton1Click(RadioButton1);
end;
 
procedure TForm1.ComboBox1Change(Sender: TObject);
begin
Image1.Picture.LoadFromFile (ListBox2.Items [ComboBox1.Tag + ComboBox1.ItemIndex]);
end;
 
end.

Image1.Picture.LoadFromFile (ListBox2.Items [ComboBox1.Tag + ComboBox1.ItemIndex]);

showMessage('сам попробуй открой файл '+ListBox2.Items [ComboBox1.Tag + ComboBox1.ItemIndex]);