The nagging possibility that there was a hardware error was never far from me during this line of questioning, and once again, the blasted hardware was at fault.

Installed the same services on another machine, watched the same routine do more or less the same things, plug the same chip into the socket and lit 'er up. Watching leds blinky blink. (just like they should)

Thank you to all who responded to my questions, appologies that there never really was anything PIC related at fault. (It's ALWAYS something stuipd)

Gary