Woah. How are you trying to get it to follow the cursor? Your code and your way
of doing it is jjaacckkeedd. Specify how you want the eye to follow the mouse
and I'll be able to help you better.

Sam

eyeFollow = function () {
var mouseDistX = this._parent._xmouse-_x;
var mouseDistY = this._parent._ymouse-_y;

var angle = 180*Math.atan2(mouseDistY, mouseDistX)/Math.PI;
var mouseDist = Math.sqrt(mouseDistX*mouseDistX+mouseDistY*mouseDistY);
var mouseDistInt = Math.floor(mouseDist/3)+1;

if (mouseDistInt>101) {
this.gotoAndStop(101);
} else {
this.gotoAndStop(mouseDistInt);
}
this._rotation = angle;
};
eyes.pupil.onEnterFrame = eyeFollow;