Weird 1120 error?!

Here is what i have:
**
60-timer_reverse1_1.addEventListener(TimerEvent.TIMER,timer_reverse1_1_event);
61-timer_reverse1_1.start();**

And I keep getting the 1120 error?

Symbol ‘slider’, Layer ‘slide out’, Frame 2, Line 60 1120: Access of undefined property timer_reverse1_1_event.

Why am I getting this, when this is where the function is defined?- so this like it is seems impossible that im getting this error…im so confused because it is just an event listener.:eyeup: -.-