关于一段监视文件操作的代码，运行出错，请大侠诊断。(50分)

我在HUBDOG.CHM原样拷贝了一段代码，是实现监视文件操作的，经试验有一处出错，
（见代码中标出的红色），请大侠看看，给出正确的代码。
{
有一个未公开函数SHChangeNotifyRegister可以把窗口添加到系统的
系统消息监视链中，该函数在Delphi中的定义如下：
Function SHChangeNotifyRegister
(hWnd //监视系统操作的窗口得句柄
,uFlags //监视操作参数
,dwEventID //监视操作参数
,uMSG //操作消息
,cItems:LongWord; //附加参数
lppsIDLSTRUCT //指定一个PIDLSTRUCT结构，该结构指定监视的目录
):integer;stdcall;external 'Shell32.dll' index 2;
当函数调用成功之后，函数会返回一个监视操作句柄，同时系统
就会将hWnd指定的窗口加入到操作监视链中，当有文件操作发生时，
系统会向hWnd发送uMsg指定的消息，我们只要在程序中加入该消息的
处理函数就可以实现对系统操作的监视了。
如果要退出程序监视，就要调用另外一个未公开得函数
SHChangeNotifyDeregister来取消程序监视。
}
unit Unit1;

interface

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

const
SHCNE_RENAMEITEM = $1;
SHCNE_CREATE = $2;
SHCNE_DELETE = $4;
SHCNE_MKDIR = $8;
SHCNE_RMDIR = $10;
SHCNE_MEDIAINSERTED = $20;
SHCNE_MEDIAREMOVED = $40;
SHCNE_DRIVEREMOVED = $80;
SHCNE_DRIVEADD = $100;
SHCNE_NETSHARE = $200;
SHCNE_NETUNSHARE = $400;
SHCNE_ATTRIBUTES = $800;
SHCNE_UPDATEDIR = $1000;
SHCNE_UPDATEITEM = $2000;
SHCNE_SERVERDISCONNECT = $4000;
SHCNE_UPDATEIMAGE = $8000;
SHCNE_DRIVEADDGUI = $10000;
SHCNE_RENAMEFOLDER = $20000;
SHCNE_FREESPACE = $40000;
SHCNE_ASSOCCHANGED = $8000000;
SHCNE_DISKEVENTS = $2381F;
SHCNE_GLOBALEVENTS = $C0581E0;
SHCNE_ALLEVENTS = $7FFFFFFF;
SHCNE_INTERRUPT = $80000000;
SHCNF_IDLIST = 0; // LPITEMIDLIST
SHCNF_PATHA = $1; // path name
SHCNF_PRINTERA = $2; // printer friendly name
SHCNF_DWORD = $3; // DWORD
SHCNF_PATHW = $5; // path name
SHCNF_PRINTERW = $6; // printer friendly name
SHCNF_TYPE = $FF;
SHCNF_FLUSH = $1000;
SHCNF_FLUSHNOWAIT = $2000;
SHCNF_PATH = SHCNF_PATHW;
SHCNF_PRINTER = SHCNF_PRINTERW;

WM_SHNOTIFY = $401;

NOERROR = 0;

type
TForm1 = class(TForm)
Memo1: TMemo;
Button1: TButton;
procedure FormClose(Sender: TObject; var Action: TCloseAction);
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
procedure WMShellReg(var Message:TMessage);message WM_SHNOTIFY;
public
{ Public declarations }
end;

type
PSHNOTIFYSTRUCT=^SHNOTIFYSTRUCT;
SHNOTIFYSTRUCT = record
dwItem1 : PItemIDList;
dwItem2 : PItemIDList;
end;

PSHFileInfoByte=^SHFileInfoByte;
_SHFileInfoByte = record
hIcon :Integer;
iIcon :Integer;
dwAttributes : Integer;
szDisplayName : array [0..259] of char;
szTypeName : array [0..79] of char;
end;
SHFileInfoByte=_SHFileInfoByte;

PIDLSTRUCT = ^IDLSTRUCT;
_IDLSTRUCT = record
pidl : PItemIDList;
bWatchSubFolders : Integer;
end;
IDLSTRUCT =_IDLSTRUCT;

function SHNotify_Register(hWnd : Integer) : Bool;
function SHNotify_UnRegister:Bool;
function SHEventName(strPath1,strPath2:string;lParam:Integer):string;
Function SHChangeNotifyDeregister(hNotify:integer):integer;stdcall;
external 'Shell32.dll' index 4;
Function SHChangeNotifyRegister(hWnd,uFlags,dwEventID,uMSG,cItems:LongWord;
lppsIDLSTRUCT):integer;stdcall;external 'Shell32.dll' index 2;
Function SHGetFileInfoPidl(pidl : PItemIDList;
dwFileAttributes : Integer;
psfib : PSHFILEINFOBYTE;
cbFileInfo : Integer;
uFlags : Integer):Integer;stdcall;
external 'Shell32.dll' name 'SHGetFileInfoA';

var

Form1: TForm1;
m_hSHNotify:Integer;
m_pidlDesktop : PItemIDList;

implementation

{$R *.DFM}

function SHEventName(strPath1,strPath2:string;lParam:Integer):string;
var
sEvent:String;
begin
case lParam of //file://根据参数设置提示消息
SHCNE_RENAMEITEM: sEvent := '重命名文件'+strPath1+'为'+strpath2;
SHCNE_CREATE: sEvent := '建立文件 文件名：'+strPath1;
SHCNE_DELETE: sEvent := '删除文件 文件名：'+strPath1;
SHCNE_MKDIR: sEvent := '新建目录 目录名：'+strPath1;
SHCNE_RMDIR: sEvent := '删除目录 目录名：'+strPath1;
SHCNE_MEDIAINSERTED: sEvent := strPath1+'中插入可移动存储介质';
SHCNE_MEDIAREMOVED: sEvent := strPath1+'中移去可移动存储介质'+strPath1+' '+strpath2;
SHCNE_DRIVEREMOVED: sEvent := '移去驱动器'+strPath1;
SHCNE_DRIVEADD: sEvent := '添加驱动器'+strPath1;
SHCNE_NETSHARE: sEvent := '改变目录'+strPath1+'的共享属性';
SHCNE_ATTRIBUTES: sEvent := '改变文件目录属性 文件名'+strPath1;
SHCNE_UPDATEDIR: sEvent := '更新目录'+strPath1;
SHCNE_UPDATEITEM: sEvent := '更新文件 文件名：'+strPath1;
SHCNE_SERVERDISCONNECT: sEvent := '断开与服务器的连接'+strPath1+' '+strpath2;
SHCNE_UPDATEIMAGE: sEvent := 'SHCNE_UPDATEIMAGE';
SHCNE_DRIVEADDGUI: sEvent := 'SHCNE_DRIVEADDGUI';
SHCNE_RENAMEFOLDER: sEvent := '重命名文件夹'+strPath1+'为'+strpath2;
SHCNE_FREESPACE: sEvent := '磁盘空间大小改变';
SHCNE_ASSOCCHANGED: sEvent := '改变文件关联';
else sEvent:='未知操作'+IntToStr(lParam);
end;
Result:=sEvent;
end;

function SHNotify_Register(hWnd : Integer) : Bool;
var
psIDLSTRUCT;
begin
{$R-}
Result:=False;
If m_hSHNotify = 0 then begin
//file://获取桌面文件夹的Pidl
if SHGetSpecialFolderLocation(0, CSIDL_DESKTOP,m_pidlDesktop)<> NOERROR then
Form1.close;
if Boolean(m_pidlDesktop) then begin
[red]ps.bWatchSubFolders := 1; //<-出错之处[/red]
ps.pidl := m_pidlDesktop;

// 利用SHChangeNotifyRegister函数注册系统消息处理
m_hSHNotify := SHChangeNotifyRegister(hWnd, (SHCNF_TYPE Or SHCNF_IDLIST),
(SHCNE_ALLEVENTS Or SHCNE_INTERRUPT),WM_SHNOTIFY, 1, ps);
Result := Boolean(m_hSHNotify);
end Else
// 如果出现错误就使用 CoTaskMemFree函数来释放句柄
CoTaskMemFree(m_pidlDesktop);
End;
{$R+}
end;

function SHNotify_UnRegister:Bool;
begin
Result:=False;
If Boolean(m_hSHNotify) Then
//file://取消系统消息监视，同时释放桌面的Pidl
If Boolean(SHChangeNotifyDeregister(m_hSHNotify)) Then begin
{$R-}
m_hSHNotify := 0;
CoTaskMemFree(m_pidlDesktop);
Result := True;
{$R+}
End;

end;

procedure TForm1.WMShellReg(var Message:TMessage); //file://系统消息处理函数
var
strPath1,strPath2:String;
charPath:array[0..259]of char;
pidlItemSHNOTIFYSTRUCT;
begin
pidlItem:=PSHNOTIFYSTRUCT(Message.wParam);
//file://获得系统消息相关得路径
SHGetPathFromIDList(pidlItem.dwItem1,charPath);
strPath1:=charPath;
SHGetPathFromIDList(pidlItem.dwItem2,charPath);
strPath2:=charPath;
Memo1.Lines.Add(SHEvEntName(strPath1,strPath2,Message.lParam)+chr(13)+chr(10));
end;

procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
begin
//file://在程序退出的同时删除监视
if Boolean(m_pidlDesktop) then
SHNotify_Unregister;
end;

procedure TForm1.Button1Click(Sender: TObject); //file://Button1的Click消息
begin
m_hSHNotify:=0;
if SHNotify_Register(Form1.Handle) then begin //file://注册Shell监视
ShowMessage('Shell监视程序成功注册');
Button1.Enabled := False;
end else
ShowMessage('Shell监视程序注册失败');
end;

end.

getmem(ps,sizeof(IDLSTRUCT));
if Boolean(m_pidlDesktop) then begin
ps.bWatchSubFolders := 1;
ps.pidl := m_pidlDesktop;
加上第一句就可以了
你是用D6编译的吧，如果是D5的就直接通过了。。。

接受答案了.