From Q1 2011 version, RadControls are no longer supported on Visual Studio 2005 and .NET 2.0. So with the later versions of RadControls, you will no longer receive .NET 2.0 versions of the Telerik AJAX
assemblies, projects or VS 2005 integration as part of the installation
packs. You can have a look at the System Requirements
for installing the latest version of Telerik RadControls.
Hope this helps,