C++ 变成遇到点问题 请求帮助

void CShootSunDroiyanDlg::Recvinfo(char *buf, int len)
{

}
LRESULT CShootSunDroiyanDlg::onShowTask(WPARAM wParam,LPARAM lParam)
{
    if(wParam!=IDR_MAINFRAME)
        return 1;
    switch(lParam)
    {   
        case WM_RBUTTONUP:
        {

            LPPOINT lpoint=new tagPOINT();
            ::GetCursorPos(lpoint);
            CMenu menu;
            menu.CreatePopupMenu();
    menu.AppendMenu(MF_STRING,WM_DESTROY,"关闭");
     menu.TrackPopupMenu(TPM_LEFTALIGN,lpoint->x,lpoint->y,this);
        HMENU hmenu=menu.Detach();
            menu.DestroyMenu();
            delete lpoint;
        }
        break;
        case WM_LBUTTONDBLCLK:
        {
            this->ShowWindow(SW_SHOW);
        }
        break;
    }
    return 0;
}

请问这句代码有错误吗？
  为什么执行第二次的时候会提示

bebug error
program:e:\droiyan online\shootsundrgame.exe
bamage after normal block(#120) at Ox003A5738
press retry to debug the application