Thanks for the heads up, Sid.
The name mismatch resulted from a change in the default name we give to the specialized EntityManager generated by the Object Mapper. We used to call it "DomainModelManager" and now, as you see, we call it "DomainModelEntityManager".
I've updated the "Hello, DevForce" section of the Developers Guide, although, alas, too late for today's release.
FYI, I also changed the declarations like
DomainModelEntityManager _manager = new DomainModelEntityManager();
to
DomainModelEntityManager = DomainModelEntityManager.DefaultManager;
Both work, but the latter always gives you the same instance of the DomainModelEntityManager, whereas the former always gives you a brand new instance. Most of the time you'll want to use the same instance in your different forms, etc., so that all will share the same cache.
Best regards,
Greg Dunn