ATMEGA168 (P/V/ 10/20 AU?) + Arduino Booloader Flashing via AVRDUDE?
It looks like the breadboard where you're burning doesn't have a crystal, although that could be hidden behind something.

Burning the bootloader will also set the fuses... which will set it to require an external oscillator.  You'll have to add an oscillator to the system to get it to talk to the ISP again.

Could that be your problem?