// AppPool
        public static int ChangeAppPoolState(int siteItemId, AppPoolState state)
        {
            // check account
            int accountCheck = SecurityContext.CheckAccount(DemandAccount.NotDemo | DemandAccount.IsActive);
            if (accountCheck < 0) return accountCheck;

            // load site item
            WebSite siteItem = (WebSite)PackageController.GetPackageItem(siteItemId);
            if (siteItem == null)
                return BusinessErrorCodes.ERROR_WEB_SITE_PACKAGE_ITEM_NOT_FOUND;

            // check package
            int packageCheck = SecurityContext.CheckPackage(siteItem.PackageId, DemandPackage.IsActive);
            if (packageCheck < 0) return packageCheck;

            // place log record
            TaskManager.StartTask("WEB_SITE", "CHANGE_STATE", siteItem.Name);
            TaskManager.ItemId = siteItemId;
            TaskManager.WriteParameter("New state", state);

            try
            {

                // change state
                WebServer web = new WebServer();
                ServiceProviderProxy.Init(web, siteItem.ServiceId);
                web.ChangeAppPoolState(siteItem.SiteId, state);

                return 0;
            }
            catch (Exception ex)
            {
                throw TaskManager.WriteError(ex);
            }
            finally
            {
                TaskManager.CompleteTask();
            }
        }