新手求助，could not compile used unit 错误

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1; myinifile:Tinifile; filename:string

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
filename: = 'd:\tor.ini'
myinifile：=Tinifile.create('d:\tor.ini');//打开D盘的 tor.ini 文件。
myinifile.readstring('[系统]','数字','缺省值')；//读取字符型数据。
ShowMessage(myinifile.readstring);
myinifile.Free；//释放INI文件。
end;
end.



错在什么地方啊