Currently, our data center only has the 2.X / 3.X / 3.5 frameworks installed on the web server.
Telerik.Web.UI.DLL contains a project reference to the System.Web.Extensions Version 1.0.61025 (i.e. .NET Framework 1.X). This means that in order for you to use the Telerik RadControls for ASP.NET, you need to have the Microsoft 1.X framework installed on your web server. For example, if you open the Telerik.Web.UI.dll in the Lutz Roeder's .NET Reflector tool, you will see that the System.Web.Extensions DLL reference is pointing to the Microsoft 1.X Framework.
Is there aother version of the Telerik.Web.UI.dll assembly that uses the .Net 3.5 version for the System.Web.Extensions?