I assume that you are using the same version of the OpenAccess Profiler as the one installed on your machine (2012.3.1209). This exception comes from WCF and most likely indicates that there is a problem with the service setup or something blocks the communication between your application and the profiler. Is it possible that your web application contains another service which might collide with the profiling service?
If you are using Visual Studio 2012 by default IIS Express is used to host the web application and you could try switching to the Visual Studio Development Server to see if it helps. You could change the hosting server from the Properties pages of the project -> Web -> Use Visual Studio Development Server.
If you are still unable to connect the profiler, you could try using its offline profiling capabilities by creating binary log files from your application and opening them later with the OpenAccess Profiler, as described in this article
Hope that helps.
All the best,
the Telerik team
Q3'12 SP1 of OpenAccess ORM packs Multi-Table Entities mapping support. Check it out.