After reading back through this thread, it appears you never burned the bootloader into the 1284P
chip yourself, but have been assuming the chip you bought has a proper bootloader burned into it.
However, given the nature of ebay, that may be a bad assumption - given comments by others
who've bought things on ebay.
So, maybe you should just try starting over and burning the bootloader yourself, using a regular
Arduino in ArduinoISP mode.
Alternatively, scrub this mission, and just buy a 1284 board from Crossroads.