Error message: Unable to cast object of type 'System.String' to type 'Bone.MultilingualString'.

Url: http://vrontinos.gr/skin.aspx?lang=el&itemtype=ProductCategory&itemid=0098BDA0&action=view&00990F9B=0099100A‡00991008‡0099100C‡00991007‡0099100D‡00991005‡0099100E&sortby=title&splitter_products_offset=24

Message: Unable to cast object of type 'System.String' to type 'Bone.MultilingualString'.

   at Bone.Base.get_Meta() in C:\Bone\Bone\src\Classes\Base.cs:line 231
   at Bone.Base.get_Head() in C:\Bone\Bone\src\Classes\Base.cs:line 355
   at ASP.skin_aspx.__Render__control1(HtmlTextWriter __w, Control parameterContainer) in c:\inetpub\wwwroot\skin.aspx:line 28
   at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
   at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer)
   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.Control.RenderControl(HtmlTextWriter writer)
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)