give me a step by step run through how to use AVR studio 5.1 with the stk500 ATMEL AVR board to program the bootloader onto the ATMEGA328P-PU this would help.
That would be doing things the hard way, since the Arduino environment (including the build and bootloader and bootloader build environment) isn't set up to use AVR Studio.
Easiest solution, use optiLoader on one of your Unos. It's been suggested to you already in other threads; have you tried it?