System.NullReferenceException: Object reference not set to an instance of an object.
   at Products_AddToCartPopup.CalculateCart() in c:\websites\Shop FuturePoint\Products\AddToCartPopup.aspx.cs:line 120
   at Products_AddToCartPopup.Page_Load(Object sender, EventArgs e) in c:\websites\Shop FuturePoint\Products\AddToCartPopup.aspx.cs:line 68
   at System.Web.UI.Control.OnLoad(EventArgs e)
   at System.Web.UI.Control.LoadRecursive()
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)