为什么出错????????

我想用ShellExecute函数来编写一个QQ强制聊天工具,但是不知道为什么我的始终不能编译通过呢?现贴出代码如下:


unit Ut_QTa;

interface

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

type
TForm1 = class(TForm)
Edit1: TEdit;
Label1: TLabel;
Button1: TButton;
StatusBar1: TStatusBar;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
var
str, str2:string;
Str2='http://wpa.qq.com/msgrd?V=1&Uin=';
str:=str2+Edit1.text;
begin
ShellExecute(0,'open','iexplore.exe',PcChar(str),SW_SHOWNORAML);
StatusBar1.Text:='NetFire 制作于2007年';
end;

end.

请大侠指出错误之处拉,下的不胜感激!!!