radiobuttons asociados a un edit

[haffo]

He puesto:

procedure TForm1.RadioGroup2Click(Sender: TObject);
begin
Edit1.Text := inttostr (RadioGroup2.Items[RadioGroup2.ItemIndex]);
end;

Pero me da un error al compilar:

[Error] Final.pas(366): There is no overloaded version of 'IntToStr' that can be called with these arguments