I just finished installing the SP1 for SL4 and tried to launch the demo from the program menu but get the following error:
Could not load file or assembly 'System.Web.Ria, Version=18.104.22.168, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified. (C:\Program Files\Telerik\RadControls for Silverlight Q1 2010 SP1\Demos\ExamplesWeb\web.config line 73)
I got the latest on SL4 and ria services but I keep getting the same error.