Audio PWM on atmega644
Your interrupt vector is incorrect.  The ISR routine looking for TIMER0_1VF_vect although you never set up the TIMER0 timer and TIMER0_1VF_vect isn't a valid vector according to atmels list.

You set up the TIMER1 to interrupt on overflow so you should use the TIMER1_OVF_vect instead which will trigger on TIMER1 overflow