Hi John Dentler,
Add the following line in your web.config file, between <controls> node
Make sure that you have System.Web.Silverlight.dll in your bin folder and it is referenced to the project.
the Telerik team
Do you want to have your say when we set our development plans?
Do you want to know when a feature you care about is added or when a bug fixed?
Telerik Public Issue Tracking
system and vote to affect the priority of the items.