I tested our demos with Blend and they are loading all fine. Could you please specify which project are you trying to open. Are they all not loading or just certain projects. With the current structure of our demos you can load the examples of just a certain control, no way to load more projects at the same time. Is the project not loading in the "Project" section of Blend studio or just the design time not showing.
Also could you try to create a new project in blend, add our dlls and then see if they are shown in the toolbox and can be added (and appear correctly) in your application.
I am trying to gather more information as we have never experienced such problem and currently I have no idea what can be wrong. Please also provide any other information that you think can help me solve the problem .
the Telerik team