RadEditor: Object reference not set to an instance of an object in Sharepoint 2013 EditPage

[yeoh]

Hi, i faced 2 problems

1. Error: Web.config registration missing! The Telerik dialogs require a HttpHandler registration in the web.config file.

I tried all the method as shown in the article, it still face the same problem. http://www.telerik.com/support/kb/aspnet-ajax/editor/details/error-web-config-registration-missing!-the-telerik-dialogs-require-a-httphandler-registration-in-the-web-config-file-

2. I got error page when i want to edit the page in Sharepoint 2013. It prompt me "Object reference not set to an instance of an object." 

Please help. Thank you. 

[yeoh]

[NullReferenceException: Object reference not set to an instance of an object.]
   Telerik.Web.SkinRegistrar.GetAllEmbeddedSkinAttributes(RadSkinManager skinManager, Type controlType, Page page) +86
   Telerik.Web.UI.Common.BaseClass.GetShortControlName(Control control) +46
   Telerik.Web.UI.Common.BaseClass.GetValueFromConfig(String keyFormat, Control control) +52
   Telerik.Web.UI.Common.BaseClass.GetGlobalEnableEmbeddedSkins(Control control) +31
   Telerik.Web.UI.RadEditor.InitiliazeDialogOpener() +161
   Telerik.Web.UI.RadEditor.CreateChildControls() +24
   System.Web.UI.Control.EnsureChildControls() +114
   Telerik.Web.UI.RadEditor.OnInit(EventArgs e) +74
   Telerik.SharePoint.SPRadEditor.OnInit(EventArgs e) +15
   System.Web.UI.Control.InitRecursive(Control namingContainer) +165
   System.Web.UI.Control.InitRecursive(Control namingContainer) +378
   System.Web.UI.Control.AddedControl(Control control, Int32 index) +214
   Microsoft.SharePoint.WebControls.TemplateBasedControl.CreateChildControls() +548
   Microsoft.SharePoint.WebControls.BaseFieldControl.CreateChildControls() +110
   Microsoft.SharePoint.WebControls.BaseTextField.CreateChildControls() +55
   Microsoft.SharePoint.WebControls.NoteField.CreateChildControls() +123
   Microsoft.SharePoint.WebControls.RichTextField.CreateChildControls() +39
   Microsoft.SharePoint.Publishing.WebControls.BaseRichField.CreateChildControls() +410
   System.Web.UI.Control.EnsureChildControls() +114
   Microsoft.SharePoint.Publishing.WebControls.RichHtmlField.OnLoad(EventArgs e) +54
   System.Web.UI.Control.LoadRecursive() +67
   System.Web.UI.Control.LoadRecursive() +164
   System.Web.UI.Control.LoadRecursive() +164
   System.Web.UI.Control.LoadRecursive() +164
   System.Web.UI.Control.LoadRecursive() +164
   System.Web.UI.Control.LoadRecursive() +164
   System.Web.UI.Control.LoadRecursive() +164
   System.Web.UI.Control.LoadRecursive() +164
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +4497