In AE CS6, I get an error message when using this inertial

bounce expression:

amp = .04;

freq = 5;

decay = 5;

n = 0;

if (numKeys > 0){

n = nearestKey(time).index;

if (key(n).time > time){

n--;

}}

if (n == 0){ t = 0;

}else{

t = time - key(n).time;

}

if (n > 0){

v = velocityAtTime(key(n).time - thisComp.frameDuration/10);

value + v*amp*Math.sin(freq*t*2*Math.PI)/Math.exp(decay*t);

}else{value}

I am using this on two position keyframes. The funny thing is that I can

preview/pre render it a few times and it works fine, then the

error message comes up randomly and then the expression is broken. What's also strange is that I am using the same expression on another comp in the same project with not problems. Pulling my hair out!

Any thoughts? Thanks!