Our online demos and the local examples, installed by default under C:\Program Files (x86)\Telerik\Reporting Q2 2014\Examples\CSharp, illustrate the proper configuration of the Silverlight Report Viewer.
More details how to add a viewer are available also in the following articles:
Please compare the settings to these in your project
and verify all files are updated correctly.
Check out the Telerik Platform - the only platform that combines a rich set of UI tools with powerful cloud services to develop web, hybrid and native mobile apps.