It sounds more complicated than a simple coding error, like starting at 1 instead of 0 in an array. I concur, since a lot of node based materials dont show in preview and even some image map stuff you really need toput a render in the workflow. It should be reported if it is still in Pro 2012 but I wont wait for a service release on P7. I too have a similar basic room prop that gave me problems with the ceiling. I gave up on it and made a more complex geometry but it will be interesting to see if its this bug.