AS3 URLRequest stored in array needs now to load, how?

Hey guys, I have a bit of code here that pulls, at random, 50 images from a file and pushes them into an array. I now need to pull, at random, 350 times from the array. I'm using a timer in place of the for loop to grab the images from the array. My code works fine as long as I do not use an array and I loop the images straight from the file. But that's very slow and bad form. I think I can do everything except the .load of the array. I can't seem to make it work. I'm getting errors that say "#1009: Cannot access a property or method of a null object reference" or "1067: Implicit coercion of a value of type Array to an unrelated type flash.net:URLRequest". I think I get the point of these messages, but I cannot seem to figure out how to pull the URLRequests back out of the array. Please, any help is much appreciated.

var imgLoader:Loader; 
var imgSource:URLRequest; 
var imgArrayer:Array = new Array(); 
var imgNum:uint; 
var timer1Count:uint; 
var thumbFade:Tween; 
var layerCount:uint = 0;  



for(var i:uint = 0; i < 50; i++) {
    imgNum = Math.random() * _imgCount;
    imgSource = new URLRequest("thumbsFinal/img"+imgNum+".jpg"); 
    imgArrayer.push(imgSource);
}


var myTimer:Timer = new Timer(_imgTrTime, _imgTrInt); 
    myTimer.addEventListener(TimerEvent.TIMER, timedFunction);
    myTimer.start();


function timedFunction(e:TimerEvent):void{
    imgLoader.load(imgArrayer);
    thumbFade = new Tween(imgLoader, "alpha", Regular.easeIn, _thumbFaderB, _thumbFaderF, _thumbFaderSpd, true);
    addChildAt(imgLoader, layerCount);
    imageAdjust();
    timer1Count+开发者_开发知识库+;
    layerCount++;


        if(timer1Count == _scrnFadeTimer) {
            screenFade();
        }
        else if(timer1Count == _txtDeploy){
            textTween();
        } 
}

this bit might be:

for(var i:uint = 0; i < 50; i++) {
    imgNum = Math.floor(Math.random() * _imgCount); 
    imgSource = new URLRequest("thumbsFinal/img"+imgNum+".jpg"); 
    imgArrayer.push(imgSource);
}

and the bit that pulls 350 times would be:

imgLoader.load(imgArrayer[Math.floor(Math.random() * (imgArrayer.length))]);

called in that timer 350 times