Thanks for all your suggestions and help. None of the suggestions resulted in getting the damn thing to work. So called Philips, ran thru the problem, explained everything that had been done to try and resolve. They concluded that the RFX was faulty.

Got my replacement unit today. Plugged it in and hey presto - no more command failed msgs! Still cannot seem to get the commands to actually work (they work in IR mode but nothing happens when the the components are set up to communicate via the RFX). Will play around some more, download the latest firmware etc, but progress!!