Ошибка Not enough actual parameters

[chubGGPK]

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, Menus, ComCtrls, jpeg, ExtCtrls, MPlayer, sSkinManager,
  sButton, ShellAPI;

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Button4: TButton;
    StatusBar1: TStatusBar;
    Image1: TImage;
    sSkinManager1: TsSkinManager;
    sButton1: TsButton;
    sButton2: TsButton;
    procedure Button1Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);

 
    procedure sButton2Click(Sender: TObject);
    procedure sButton1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

uses Unit3, Unit2, Unit4, Unit5;

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
form4.show;
form2.hide;
form1.Hide;
end;

procedure TForm1.Button4Click(Sender: TObject);
begin
close;
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
form3.Show;
form1.Hide;
end;





procedure TForm1.sButton2Click(Sender: TObject);
begin
form5.show;
form2.hide;
form1.Hide;
end;



procedure TForm1.sButton1Click(Sender: TObject);
begin
ShellExecute(ShellExecute(Handle,'open', PChar('my.chm'),nil, nil, SW_SHOWNORMAL);

end;

end.

Ругается на
procedure TForm1.sButton1Click(Sender: TObject);
begin
ShellExecute(ShellExecute(Handle,'o pen', PChar('my.chm'),nil, nil, SW_SHOWNORMAL);

[Человек_Борща]

1. что эта тема делает НЕ в своем разделе?
2. что за бредовый дабл-вызов?

ShellExecute(ShellExecute(Handle,'open', PChar('my.chm'),nil, nil, SW_SHOWNORMAL);