Unfortunately, we do not support .NET 3.5 anymore. This is why I would like to inspire you to upgrade to version of the framework that we support. You can find more information about our requirements in the System Requirements article
Please consider upgrading and test our latest official binaries to check if the latest behavior fits your scenario.
Pavel R. Pavlov
Check out Telerik Analytics, the service which allows developers to discover app usage patterns, analyze user data, log exceptions, solve problems and profile application performance at run time. Watch the videos
and start improving your app based on facts, not hunches.