Hi Satish J,
You should include a reference to all necessary assemblies that are used in the solution. Note that the Input_SL should be Telerik.Windows.Controls.Input as we did a mistake while sending the project.
We have distributed our controls in several assemblies under the same namespace e.g. Telerik.Windows.Controls, so if anything is missing from this namespace you probably don't have the assembly containing the class part of your solution.
Thank you for contacting us and I hope this will resolve your issue.
the Telerik team