Are the errors of type
"The name X does not exist in the namespace Y"? Could you elaborate on the upgrade procedure you used?
A possible reason for the behavior is if the design assemblies for the controls are resolved from a different location (like your local installation of the latest official release) than the actual assemblies (from the LIB) used in the project. Usually upgrading your project with the upgrade wizard will prevent this, so please let me know what are the steps you executed and we will further look into the case. In the meantime, you could uninstall the official release of the suite.
Do you want to have your say when we set our development plans? Do you want to know when a feature you care about is added or when a bug fixed? Explore the Telerik Feedback Portal
and vote to affect the priority of the items