Possible fake testing with Rhino mock
As far as I can understand (I use Moq as an isolation framework and not rhino mocks) in your test you are testing not an implementation of your class FillTableRow, but a mock, generated by isolation framework. You should always use your real class as systam under test (obviously). You use stubs to provide context in which your system under tests works, just to emulate the system's environment. And you use mocks if the state of your system under test is not changing during your test and you need to be sure that correct methods of external classes has been called.
I recomend you to read "The Art of Unit Testing" book by Roy Osherove. It gives very good explanation of how and when you should use mocks and stubs.