There is a 3 versions of Club Starter kit in "community Starter kits " page , make sure to install the asp,net 3.5 version .
you can also install the old versions of the starter kit , if you want to use starter kit that is buil for .net 2.0 , you need to make sure that you changed some ajax dll version from your web.config file ,
and also you need to make sure that you installed Ajax extensions for asp.net 2.0 ,because its required for asp.net 2 to support ajax .
asp.net 3.5 doesn't need to isntall the mentioned ajax extensions , because the extensions is built in the framework.