We have not yet updated the MsWordAdapter assembly to support the RadSpell for ASP.NET AJAX.
You will need the two MS Office interop dlls (Microsoft.Vbe.Interop.dll and Microsoft.Office.Interop.Word.dll) in the bin folder of your application. Next you will need to put the attached MSWordAdapter.cs file in your application's App_Code folder. Finally, you need to set the SpellCheckProviderTypeName property of the RadSpell control to point to the WordSpellCheckProvider class in the MSWordAdapter.cs file. For example:
RadSpell1.SpellCheckProviderTypeName = typeof(Telerik.Web.UI.WordSpellCheckProvider).AssemblyQualifiedName;
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