Error message: Object reference not set to an instance of an object.

Url: http://allforoffice.gr/skin.aspx?lang=en&itemtype=Product&itemalias=-0000015467&action=view&

Message: Object reference not set to an instance of an object.

   at Ecommerce.Product.get_UserPrice() in C:\Bone\Ecommerce\src\DBItems\Product\Product.cs:line 484
   at Ecommerce.Product.get_PriceBeforeDiscount() in C:\Bone\Ecommerce\src\DBItems\Product\Product.cs:line 505
   at ASP.tpl_head_tpl_ascx.__Render__control1(HtmlTextWriter __w, Control parameterContainer) in c:\inetpub\allforoffice\tpl\Head.tpl.ascx:line 143
   at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
   at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter)
   at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
   at Bone.Base.get_HeadMinified() in C:\Bone\Bone\src\Classes\Base.cs:line 530
   at ASP.skin_aspx.__Render__control1(HtmlTextWriter __w, Control parameterContainer) in c:\inetpub\allforoffice\skin.aspx:line 25
   at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
   at System.Web.UI.Page.Render(HtmlTextWriter writer)
   at Bone.Asp.RenderSkin(TextWriter w) in C:\Bone\Bone\src\Classes\Asp.cs:line 71
   at Bone.ModalAction.RenderPage(TextWriter w) in C:\Bone\Bone\src\Actions\Modal.cs:line 81
   at Bone.Asp.Render(HtmlTextWriter w) in C:\Bone\Bone\src\Classes\Asp.cs:line 82
   at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter)
   at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)