Is it possible that one of your referenced assembly is missing the OpenAccess node in its configuration file? For example if you have an assembly that hold your persistent classes and another assembly that holds the reports and only the assembly holding the records is configured this might rise an exception. If that is not the case can you please provide us with some additional information on your setup so that we can reproduce the problem here locally. We are looking forward for your replay.
All the best,
the Telerik team