issue with tab bar view displaying a compound view

Answer 1

The File's Owner should be a class that you instantiate. For example, in your contentNib file, you should alloc and init a table view, passing the @"contentNib" as the argument to initWithNibNamed:bundle:. It sounds like you're not doing this, as the File's Owner, while set in IB to a UITableViewController, is actually just a UIViewController.

The setting in IB is just to let IB know what outlets and actions to make available; you are responsible for providing the proper object.