CMDIFrameWnd::OnCreate(lpCreateStruct) causing trouble while creating mdi with menu

I tried to create a mdi with a menu without using appwizard

but it is displaying assertion error when i add the code of OnCreate()and when i debug it.It is displaying hMenu=-1 but

when i comment it .the mdi gets displayed but with out frame. please anyone tell me what is the mistake i have had done

mdi.cpp

#include<afxwin.h>

#include<afxext.h>

#include "resource.h"

class Win:public CWinApp

{

public:

BOOL InitInstance();

};

class Frame:public CMDIFrameWnd

{

public:

Frame();

private:

afx_msg int OnCreate(LPCREATESTRUCT lpCreatestruct);

virtual BOOL PreCreateWindow(CREATESTRUCT& cs);

private:

DECLARE_MESSAGE_MAP()

};

BEGIN_MESSAGE_MAP(Frame,CMDIFrameWnd)

ON_WM_CREATE()

END_MESSAGE_MAP()

Frame::Frame(){

}

BOOL Frame::PreCreateWindow(CREATESTRUCT& cs)

{

return CMDIFrameWnd::PreCreateWindow(cs);

}

int Frame::OnCreate(LPCREATESTRUCT lpCreateStruct)

{

if(!CMDIFrameWnd::OnCreate(lpCreateStruct))//this is the part causing

//error for me

return -1;

return 0;

}

BOOL Win::InitInstance()

{

Frame* f1=new Frame;

f1->LoadFrame(IDR_MENU1);

m_pMainWnd=f1;

m_pMainWnd->ShowWindow(3);

m_pMainWnd->UpdateWindow();

return TRUE;

}

Win W1;

resource.h

//{{NO_DEPENDENCIES}}

// Microsoft Developer Studio generated include file.

// Used by Script1.rc

//

#define IDR_MENU1 101

#define ID_MENUITEM40001 40001

#define ID_MENUITEM40002 40002

#define ID_MENUITEM40003 40003

#define ID_MENUITEM40004 40004

#define ID_MENUITEM40005 40005

#define ID_BUTTON40006 40006

#define ID_BUTTON40007 40007

// Next default values for new objects

//

#ifdef APSTUDIO_INVOKED

#ifndef APSTUDIO_READONLY_SYMBOLS

#define _APS_NEXT_RESOURCE_VALUE 106

#define _APS_NEXT_COMMAND_VALUE 40008

#define _APS_NEXT_CONTROL_VALUE 1000

#define _APS_NEXT_SYMED_VALUE 101

#endif

#endif

or any one tell me How to create a MDI window with a menu without using appwizard.

Thank you

By Balasubramaniam.J