1136: Incorrect number of arguments. Expected 1.

Hi There

I have a main class file and another class file with a function in that I want to call from the main class. when I addChild the second class in the main class file I get 1136 error - incorrect number of arguments.

How do I solve this error message?

Here is the code in my main class file:

package

{

    import flash.display.*;

    import flash.utils.*;

    import flash.events.*;

    import flash.media.*;

    import flash.text.*;

    public class BugGoopFSGame extends MovieClip

    {

        public var mybackground:BackGround;

        public var cinders:Cinders;

        public var gameTimer:Timer;

        public var spidy:Spidy;

        public var myplaybtn:Play;

        public var timerback:TimerBack;

        public var timermiddle:TimerMiddle;

        public var timerfront:TimerFront;

        public var settings_btn:Settings_btn;

        public var sound1:Sound1 = new Sound1();

        public var sound3:Sound3 = new Sound3();

        public var channel:SoundChannel = sound1.play(0,int.MAX_VALUE)

        public var st:SoundTransform = channel.soundTransform;

        public var scoreText:ScoreText = new ScoreText();

        var wordArray:WordArray;

        public var wordtext:wordText;

        public var letterA = new A ();

        //**Constructor Function

            public function BugGoopFSGame()

        {

           gameTimer = new Timer(31,5120);

            //Add event listener for start button

            myplaybtn.addEventListener(MouseEvent.CLICK, startTimer);

            }

            //Start timer function

        public function startTimer(timerEvent:MouseEvent):void

        {

            gameTimer.start();

            trace("Game Timer started");

            myplaybtn.visible = false;

           scoreText = new ScoreText();

            addChild(scoreText);

            wordtext = new wordText();

            addChild(wordtext);

            trace("WordText Box Added");

            wordArray = new WordArray(); //as soon as I add this, I get the error message

            addChild(wordArray);

            wordArray.showLetter();

        }