ok I just wrote it on a notepad since I cannot test it, this goes on the main timeline, & does all the jobs so maybe you should not have any program written inside movieclips besides "stop();"

Somethings to check if there are still errors:
setinterval is written properly for as2?
movieclip linkage names are spelled correct case for the attachmovieclip?


PHP Code:
//Share this with AS3.0 for help
var score 0;
var 
check_interval=null
var check_time=1000//every 1000 milliseconds, check if fairy count is too low to spawn more
var check_enabled=false
var fairy_array = []
var 
fairy_death_spawn_array=[]
var 
fairy_death_duration=700//ms
var MAXFAIRY 10;
var 
FAIRYINDEX=0
var playerSpeed=35
    
//Setings for the game
var SPEEDER 6;
    
//positive speed for the fairy
var NEGSPEEDER = -6;
    
//negtive speed for the fairy
var LEFT 0;
    
//x = 0
var TOP 0;
    
//y = 0
var BOTTOM stage.stageHeight-50
    
//y = 718
var RIGHT stage.stageWidth-50;

//stop();
var current_depth=10;
init();
//spawn player and faries
current_depth++
attachMovie("Swatter""Swatter"current_depth);


//var swatter_var:Swatter=new Swatter()
//stage.addChild(swatter_var);
//swatter_var.name="Swatter"
//attach the swatter

 
_root["Swatter"]._x 300;
//swatter ccordinates
 
_root["Swatter"]._y 200;
//swatter ccordinates



    //Spawncap for the fairies

function init() {
    
fairy_array =[]
    
fairy_death_spawn_array=[]
SPEEDER 6;
    
//positive speed for the fairy
NEGSPEEDER = -6;
    
//negtive speed for the fairy
LEFT 0;
    
//x = 0
TOP 0;
    
//y = 0
BOTTOM Stage.height-50
    
//y = 718
RIGHT =Stage.width-50;
MAXFAIRY 10;
    
FAIRYINDEX=0
    
//Spawncap for the fairies

    //Fairy Array
    ///createEmptyMovieClip("fairy_spawn", 0);
//var fairy_spawn_var:Fairy=new Fairy()
//stage.addChild(fairy_spawn_var);
//fairy_spawn_var.name="fairy_spawn_var"
    ///movieclip where fairies spawn in
    
fairyinit();
}

function 
fairyinit() {
    
//settings for the fairies
    
FAIRYINDEX 0;
    
//Set the current spawn to 0
while (FAIRYINDEX<MAXFAIRY) {
spawnFairy();
}
FAIRYINDEX=MAXFAIRY

    
//when the fairy number is below the spawn cap, spawn faries periodically. However, flash crashes when I try to use the interval, perhaps an issue with flash trying to cound how many movieclips are on the canvas and running the setInterval code at the same time
check_enabled=true
//check_interval=setTimeout(lowFairyCountCheck,check_time);
setInterval(lowFairyCountCheckcheck_time);
}

function 
lowFairyCountCheck(){
if(
check_enabled){
trace("check " FAIRYINDEX)
while (
FAIRYINDEX<MAXFAIRY) {
spawnFairy();
}


}
}
function 
spawnFairy() {
    
//Code for when the fairy is spawned. This determines the speed, the coordinates, and runs the function for the movement

//    var fairy_spawn_var:Fairy=new Fairy()//create fairy variable
//stage.addChild(fairy_spawn_var);//add it to stage
//fairy_spawn_var.name="fairy_spawn_var"//give it a name to access as stage.getChildByName("fairy_spawn_var").x etc..
current_depth++;
    
attachMovie("Fairy""Fairy"+current_depthcurrent_depth);
    
    
//trace(fairy_clip);
     
_root["Fairy"+depth_num].NEGVELX Math.random()*NEGSPEEDER;
     
_root["Fairy"+depth_num].NEGVELY Math.random()*NEGSPEEDER;
     
_root["Fairy"+depth_num].VELX Math.random()*SPEEDER;
     
_root["Fairy"+depth_num].VELY Math.random()*SPEEDER;
     
_root["Fairy"+depth_num]._x Math.random()*RIGHT;
     
_root["Fairy"+depth_num]._y Math.random()*BOTTOM;
    
//fairy_spawn_var.onEnterFrame = fairymove;
    
fairy_array.push_root["Fairy"+depth_num]);//The fairy enemy
    
FAIRYINDEX++



}
onEnterFrame=function(){

for(var 
i=0;i<fairy_array.length;i++){
    if (
fairy_array[i].hitTest(Wall) == true) {
fairy_array[i]._x += fairy_array[i].VELX;
fairy_array[i]._y += fairy_array[i].VELY;
fairy_array[i]._x += fairy_array[i].NEGVELX;
fairy_array[i]._y += fairy_array[i].NEGVELY;

        }else{
            
unloadMovie(fairy_array[i])//unload fairy that left the wall
            
fairy_array.splice(i,1)//remove fairy from array space
            
FAIRYINDEX--;//subtract the index so that more fairies missing can be added later if needed.
        
}

}

/*

    if (this.hitTest(Wall) == false) {//The goal of the faries is to swat them down before they leave the field. Planning on having this deducting 3 points from the score.
        unloadMovie(this);
    }
*/
}


//Player Controls: WASD for movement, P for swatting
// A is 65
// S is 83
// D is 68
// W is 87

var Attack_Fairy:Object = new Object();
Attack_Fairy.onKeyDown = function() {
    if (
Key.getCode() == "80") {
    
Splat();
kill();
    }
        if (
Key.getCode() == "87") {//w
         
_root["Swatter"]._y-=playerSpeed
        
}
        
        if (
Key.getCode() == "65") {//a
         
_root["Swatter"]._x-=playerSpeed
        
}
        if (
Key.getCode() == "83") {//s
         
_root["Swatter"]._y+=playerSpeed
        
}
        if (
Key.getCode() == "68") {//d
         
_root["Swatter"]._x+=playerSpeed
        
}
};

/*
stage.addEventListener(KeyboardEvent.KEY_DOWN,kd)
function kd(e:*){
if(e.keyCode=="80"){
Splat();
kill();
}
if(e.keyCode=="87"){//W
//Key.addListener(Attack_Fairy);
stage.getChildByName("Swatter").y -= playerSpeed;
}
if(e.keyCode=="65"){//A
//Key.addListener(Attack_Fairy);
stage.getChildByName("Swatter").x -= playerSpeed;
}
if(e.keyCode=="83"){//S
//Key.addListener(Attack_Fairy);
stage.getChildByName("Swatter").y += playerSpeed;
}
if(e.keyCode=="68"){//D
//Key.addListener(Attack_Fairy);
stage.getChildByName("Swatter").x+= playerSpeed;
}

}
*/
function kill(){
for(var 
i=0;i<fairy_array.length;i++){
if (
fairy_array[i].hitTest(_root["Swatter"]) == true) {
//var fairy_death_spawn_var:Fairy_death=new Fairy_death()
//stage.addChild(fairy_death_spawn_var);
//fairy_death_spawn_var.name="fairy_death_spawn_var"
current_depth++
attachMovie("Fairy_death""Fairy_death"+current_depthcurrent_depth);
fairy_death_spawn_array.push(_root["Fairy_death"+depth_num]);//The fairy enemy
    
_root["Fairy_death"+depth_num]._x=fairy_array[i]._x
_root
["Fairy_death"+depth_num]._y=fairy_array[i]._y
//setTimeout(removeFairyDeath,fairy_death_duration) ------------------------------------------------------required
unloadMovie(fairy_array[i])//unload fairy that left the wall
fairy_array.splice(i,1)//remove fairy from array space
FAIRYINDEX--;//subtract the index so that more fairies missing can be added later if needed.
}
}
}

function 
removeFairyDeath(){
//while(fairy_death_spawn_array[0].name=="hit"){//---------------------------------------------------------required
//unloadMovie(fairy_death_spawn_array[0])//unload splat
//fairy_death_spawn_array.shift()
//}
if(fairy_death_spawn_array.length>0){
unloadMovie(fairy_death_spawn_array[0])//unload fairy death
fairy_death_spawn_array.shift()
}
}

function 
Splat() {
depth_num++
    
attachMovie("hit""hit"depth_num);
    
//var hit_var:hit=new hit()//attach for as3
    //stage.addChild(hit_var)//add to stage
    //hit_var.name="hit"//give name
    
    //hit_var._x = Swatter._x;
    //hit_var._y = Swatter._y;
    //hit_var.x = stage.getChildByName("Swatter").x;
    //hit_var.y = stage.getChildByName("Swatter").y;
//    fairy_death_spawn_array.push(_root["hit"]);//add to same array as fairy death for removing both at once later
    
}



//playSound(placeholder_DnB)
//playSound(Controls)
//function playSound(a){
//var snd:Sound=new a()
//snd.play()
//}
//SoundMixer.stopAll() //stop all sounds
/*

//soundtrack is a placeholder
// Play Sound Behavior
_global.Behaviors.Sound.placeholder_spunk.start(0, 1);
// End Play Sound Behavior
//Play Internal Sound Behavior
if (_global.Behaviors == null) {
    _global.Behaviors = {};
}
if (_global.Behaviors.Sound == null) {
    _global.Behaviors.Sound = {};
}
if (typeof this.createEmptyMovieClip == 'undefined') {
    this._parent.createEmptyMovieClip('BS_placeholder_spunk', new Date().getTime()-(Math.floor((new Date().getTime())/10000)*10000));
    _global.Behaviors.Sound.placeholder_spunk = new Sound(this._parent.BS_placeholder_spunk);
} else {
    this.createEmptyMovieClip('_placeholder_spunk_', new Date().getTime()-(Math.floor((new Date().getTime())/10000)*10000));
    _global.Behaviors.Sound.placeholder_spunk = new Sound(this.BS_placeholder_spunk);
}
_global.Behaviors.Sound.placeholder_spunk.attachSound("placeholder_DnB.mp3");
if (true) {
    _global.Behaviors.Sound.placeholder_spunk.start(0, 1);
}
//End Behavior                                                                                                      
*/ 
If you still have an issue you can just take parts from the program and put it in yours