You can use another version of SQL Server by modifying the connection string in our Examples.CS or Examples.VB projects. For more information please visit this forum thread - http://www.telerik.com/community/forums/wpf/general-discussions/can-t-run-the-demo.aspx
The Northwind database is not installed by our installation scripts but you can download it from here
and populate the Northwind for any version of SQl Server from 2000 and up.
Do not hesitate to contact us if you have any more questions.
the Telerik team