Child object not detected - actionscript-3

Question

Why can't it detect these declared image objects- m22,m33....?
TypeError: 2007 Error #: Parameter child must be non-null.
The code runs fine until choosetext function then errors.
mode traces display.
Other traces display.
Yaddah Yaddah
boxtrans is a transparent sprite to mask mouse input.
package {
import flash.display.Bitmap;
import flash.display.Sprite;
import flash.events.*;
import flash.ui.Keyboard;
import mx.core.BitmapAsset;
//import board;
import flash.accessibility.AccessibilityImplementation;
import flash.display.MovieClip;
import flash.text.TextField;
import flash.text.TextFormat;
import flash.display.Sprite;
import flash.utils.ByteArray;
import flash.events.MouseEvent;
import flash.text.AntiAliasType;
import flash.utils.describeType;
import flash.net.*;
import Set;
import StatusBox;
import Statusx;
import flash.display.InteractiveObject;
import flash.text.TextFieldType;
import flash.events.FocusEvent;
import fl.managers.FocusManager;
import flash.display.*;
import flash.display.Stage;
import flash.events.KeyboardEvent;
import flash.utils.*;
import boxtrans;
public class boxsprite extends Sprite {
[Embed(source = "C:/Windows/Fonts/Verdana.ttf", fontName = "Verdana", fontWeight = "bold", advancedAntiAliasing = "true", mimeType = "application/x-font")]
public static const VERD:Class;
[Embed(source="../lib/box.gif")]
private var boxspriteClass:Class
[Embed(source = "../lib/m2.gif")]
private var m2:Class
[Embed(source = "../lib/m3.gif")]
private var m3:Class
[Embed(source="../lib/m4.gif")]
private var m4:Class
[Embed(source = "../lib/m5.gif")]
private var m5:Class
[Embed(source = "../lib/m6.gif")]
private var m6:Class
[Embed(source = "../lib/m7.gif")]
private var m7: Class
[Embed(source="../lib/m8.gif")]
private var m8: Class
[Embed(source = "../lib/m9.gif")]
private var m9: Class
internal var m22:Bitmap;
internal var m33:Bitmap;
internal var m44:Bitmap;
internal var m55:Bitmap;
internal var m66:Bitmap;
internal var m77:Bitmap;
internal var m88:Bitmap;
internal var m99:Bitmap;
internal var boxsprite2:Bitmap;
internal var boxtrans1:Sprite;
internal var mode:uint=2;
internal var displaytext:String;
internal var setBox:Boolean = false;
internal var onBoard:Array = [0];
internal var playerRound:uint = 1;
internal var round:uint = 1;
internal var playernumber:uint;
internal var myTextBox:TextField = new TextField();
public function boxsprite():void {
init();
}
internal function init():void {
boxsprite2=new boxspriteClass as Bitmap;
this.addChild(boxsprite2);
m77= new m7 as Bitmap;
this.addChild(m77);
m66= new m6 as Bitmap;
this.addChild(m66);
m55= new m5 as Bitmap;
this.addChild(m55);
m44= new m4 as Bitmap;
this.addChild(m44);
m33= new m3 as Bitmap;
this.addChild(m33);
m22 = new m2 as Bitmap;
this.addChild(m22);
boxtrans1 = new boxtrans() as Sprite;
boxtrans1.x = 0;
boxtrans1.y = 240;
this.addChild(boxtrans1);
this.addEventListener(MouseEvent.CLICK, clickDoubleClick);
}
internal var m_nDoubleClickSpeed:Number = 300;
internal var m_toMouse:Number;
internal function clickDoubleClick(e:MouseEvent):void {
if (isNaN(m_toMouse)==false) {
clearTimeout(m_toMouse);
HandleDoubleClick();
} else {
m_toMouse = setTimeout(HandleSingleClick, m_nDoubleClickSpeed);
}
}
internal function HandleSingleClick():void {
trace("HandleSingleClick");
m_toMouse = NaN;
}
internal function HandleDoubleClick():void {
modeswitch();
trace("HandleDoubleClick");
m_toMouse = NaN;
}
internal function modeswitch():void{
trace(mode);
switch(mode) {
case 8:
{mode = 9;
choosetext(); }
case 9:
{mode = 2;
choosetext();
}
case 2:
case 3:
case 4:
case 5:
case 6:
case 7:
{mode +=1;
choosetext(); }
}
}
internal function choosetext():void {
switch (mode) {
case 2: {this.setChildIndex(m22,this.numChildren - 1);}
case 3: {this.setChildIndex(m33,this.numChildren - 1);}
case 4: {this.setChildIndex(m44,this.numChildren - 1);}
case 5: {this.setChildIndex(m55,this.numChildren - 1);}
case 6: {this.setChildIndex(m66,this.numChildren - 1);}
case 7: {this.setChildIndex(m77,this.numChildren - 1);}
case 8: {this.setChildIndex(m88,this.numChildren - 1);}
case 9: {this.setChildIndex(m99,this.numChildren - 1); }
}
}
}
}

Answer 1

It looks like you are not instantiating m88 or m99 anywhere.
Since you don't have any breakcommands in your switch statement it falls through and executes every case even if mode is only 2.
I'm assuming you meant to do something like this:
switch (mode) {
case 2:
this.setChildIndex(m22,this.numChildren - 1);
break;
case 3:
this.setChildIndex(m33,this.numChildren - 1);
break;
// etc...
}