[Kis]

Код:

procedure TEditPersonsForm.RadioGroup1Click(Sender: TObject);
begin
if radiogroup1.ItemIndex=0 then
  opencomport;
if radiogroup1.ItemIndex=1 then
  begin
 closecomport;
  end;

end;


procedure TEditPersonsForm.closecomport;
begin
  rt.Terminate;
  CloseCom(ftHandle);
end;

procedure TEditPersonsForm.opencomport;
begin
  ftHandle := InitCom(0);
  if ftHandle <> COMInvHandle then
  begin
    rt := TReadCardThread.Create(true);
    rt.HWND := Handle;
    rt.usb := ftHandle;
    rt.Resume;
  end else
  begin
  end;
end;

выходит ошибка {access violation at address 00425EBC in module 'project1.exe'. Write of address 0000000D}

не подскажите как исправить?