I am getting a 1056 error in my custom class file and cannot figure out why... Help

Question

Here is the error I am getting:
ReferenceError: Error #1056: Cannot create property button1 on com.sample.PWClass.PClass.
Here is my code:
package com.sample.PWClass {
    import flash.display.MovieClip; 
    import flash.events.MouseEvent; 
    import flash.text.TextField; 
    public class PClass extends MovieClip { 
        private var totalChar=8;// number of chars in the password 
        private var xcom:String="abcdefghijklmnpqrstuvwxyzABCDEFGHIJKLMNPQRSTUVWXYZ"; 
        private var xcomnum:String="0123456789"; 
        private var l_length=xcom.length; 
        private var n_length=xcomnum.length; 
        private var new_password:String=new String();// set the inital variable 
        public function PClass() { 
            button1.addEventListener(MouseEvent.CLICK,onClickHandler); 
        private function onClickHandler(evt:MouseEvent):void { 
            mark.text = newPassword(); 
            trace(mark.text); 
        private function newPassword() { 
            new_password=new String(); 
            for (var i=0; i < totalChar; i++) {// loop and create password 
                var a=xcom.charAt(Math.floor(Math.random() * l_length)); 
                var b=xcomnum.charAt(Math.floor(Math.random() * n_length)); 
                var char=Math.floor(Math.random() * totalChar) % 2 == 0?a:b; 
                new_password+= char; 
            return new_password; 

Answer 1

If this is not your document class, since button1 is not created within the class, there is nothing provided to reference it as an external object.  You need to pass in a reference to it.