<!--CodeS-->
program prj_helpdesk;

uses
  Forms,
  Umain in 'Umain.pas' {frm_main},
  Udm in 'Udm.pas' {dm: TDataModule};

{$R *.res}
var lWND : longint;
var HMutex:LongInt;
begin
  HMutex := CreateMutex(nil,TRUE,'prj_helpdesk');    <---[Error] prj_helpdesk.dpr(12):            
                                                                                     Undeclared identifier: 'CreateMutex'
  if (GetLastError = ERROR_ALREADY_EXISTS) then
  begin
    //Application.MessageBox('프로그램이 이미 실행 되어 있습니다.', '확인', MB_OK + MB_ICONSTOP);
    lWND:=FindWindow(pChar(0),'prj_helpdesk');
    if lWND<>0 then
    begin
      SetForegroundWindow(lWND);
      if IsIconic(lWND) then ShowWindow(lWND, SW_RESTORE);
    end;

    Halt;
  end;

  Application.Initialize;
  SetWindowText(Application.Handle,'prj_helpdesk');
  Application.CreateForm(TDM, DM);
  // 로그인...
  Frm_Login := TFrm_Login.Create(Application);
  Frm_Login.ShowModal;
  if Not Frm_Login.m_IsLogin then
  begin
    if HMutex <> 0 then CloseHandle(HMutex);
    Frm_Login.Free;
    Halt;
  end
  else
  begin
  Application.Initialize;
  Application.CreateForm(Tfrm_main, frm_main);
  Application.CreateForm(Tdm, dm);
  Application.Run;
end.
<!--CodeE-->

위 소스에서 CreateMutex에서 에러가 납니다
혹 다른 dll이나 파스가 있어야만 하는것인지
고수님의 현답을 부탁드립니다.