Please, give us more information about the following questions:
- do you have installed the TelerikUI controls for WPF?
- if you have it, is this a first time you're installing the controls or you had previous installations? - here
, under Demos Application section, you can find an info what needs to be done in this case;
- is this situation happening only when you're trying to run the RadRadialMenu demos or with all demos in the suite?
Please, excuse us for the caused inconvenience.
Looking forward to your answer.
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.