我怎么解决这个错误

正如您看到的,这是一个类创建4个文本字段,我要做的是在这行代码中 第一个1[i].text=k1[i]; 在for循环中,在文本字段中写入随机数

那是我的密码

import flash.display.Sprite;
            import flash.display.DisplayObjectContainer;
        import flash.display.InteractiveObject;
        import flash.text.TextField;
        import flash.text.TextFormat;
        import flash.events.MouseEvent;
        import flash.events.KeyboardEvent;

    public class addClass  extends Sprite {
                        public var first1:Array = new Array();
                                public var i:uint;
                               public var k1:Array = new Array();

                 public function addClass() {
                       for (i= 1 ; i<= 5; i++)
        {       first1[i]= createCustomTextField(100,(i*40),50,30);
                            k1[i]=Math.round(Math.random()*10);
                    // here is the problem
                       first1[i].text = k1[i];
               }


                 private function createCustomTextField(x:Number, y:Number, width:Number, height:Number):TextField
               {
                var result:TextField=new TextField  ;
                var format:TextFormat = new TextFormat();
                result.x=x;
                result.y=y;
                result.width=width;
                result.height=height;
                result.background=false;
                result.border=true;
                result.selectable=false;
                result.restrict="0-9";
                format.size = 24; 
                format.color = 0xFFFFFF;
                result.defaultTextFormat = format;
                addChild(result);
                return result;
                }