Double check the connections and that the target processor is getting power
on all its Vcc and AVcc pins, and ground on all the ground pins.
Check it has decoupling on each supply pin, and is an ATmega328P (the P is important,
otherwise you'll have to create a new entry in boards.txt).
Always connect the target board after the host has been programmed with the ArduinoISP
sketch - then power both boards up. You don't want any junk on the ISCP header
before programming.