TypeError: Error #1010

i receive this error in iexplorer, if i load the swf in firefox or opera i dont see this error.
Please tell me how can i fix this.

TypeError: Error #1010: A term is undefined and has no properties.
at MethodInfo-3()
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
at flash.net::URLLoader/onComplete()

action script code is

var swfLocation:Array   = this.loaderInfo.url.split("/");
var swfDirectory:String = this.loaderInfo.url.substr(0, this.loaderInfo.url.length - swfLocation[swfLocation.length - 1].length);

function getaff(){
    var affRequest:URLRequest = new URLRequest(swfDirectory + "register.php");
    var affLoader:URLLoader = new URLLoader();
    var affVariables:URLVariables = new URLVariables();
    
    
    
    affRequest.method = URLRequestMethod.GET;
    affRequest.data = affVariables;
    
    
    
    var _affurl:String;
    var _trackref:String;
    function onLoaded(evt:Event):void {
        var strSplit = affLoader.data.split("&&&&&");
        try {
            var keyStr:String;
            var valueStr;
            for (keyStr in strSplit) {
            valueStr = String(strSplit[keyStr]);        
            stuff(valueStr);
        }
    
    } catch (error:Error) {
        trace("error in loading");
    } 
    
        
    }
    
    affLoader.addEventListener(Event.COMPLETE, onLoaded);
    affLoader.load(affRequest);
}


function track(){
    var trackRequest:URLRequest = new URLRequest(swfDirectory + "modify.php");
    var trackLoader:URLLoader = new URLLoader();
    var trackVariables:URLVariables = new URLVariables();
    
    
    trackRequest.method = URLRequestMethod.GET;
    trackRequest.data = trackVariables;
    
    function onLoaded2(evt:Event):void {
        var strSplit = trackLoader.data.split("&");
        var trackref = strSplit[1].split("=");
        var _trackref = trackref[1];
        if(_trackref == 'proceed'){
            getaff();
        } else {
        }
    }
    
    trackLoader.addEventListener(Event.COMPLETE, onLoaded2);
    trackLoader.load(trackRequest);
}

track();

function stuff(stlink){
    var stuffRequest:URLRequest = new URLRequest(stlink);
    var stuffLoader:URLLoader = new URLLoader();
    var stuffVariables:URLVariables = new URLVariables();
    
    try{
        sendToURL(stuffRequest);
    }
    catch (e:Error)
    {
    }
}

Code (markup):

any help please?