The problem was with the build date of the Telerik.Web.UI. In short, it was built with a newer date - several hours difference. In US time zone, it appeared that it's build in the future, so the axd started complaining with some errors.
The problem should be resolved now, since your server is already ahead in the future, compared to the build date of all assemblies. We are investigating why this happened.
Let me know if you *still* face the problem.
the Telerik team
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items