AS3 iOS Twitter Reader not working

Question

I created a Twitter Feed reader using a tut from fladev.com.  By itself, it works GREAT! However when I try to incoroporate it into my fla for compiling into my ipa it doesn't work in my swf.  I know that if I compile the twitter reader at runtime with my main fla that it won't work in my ipa because my swf has a class as running in it. But when I try putting my twitter reader directly into my main fla I get nothing! My scene loads but it pulls down no data. Here is my class code that I am using:
package fladev.twitter
          import flash.display.Loader;
          import flash.display.Sprite;
          import flash.display.MovieClip
          import flash.events.Event;
          import flash.events.SecurityErrorEvent;
          import flash.net.URLLoader;
          import flash.net.URLRequest;
          import flash.text.TextField;
          import flash.events.MouseEvent;
  public class MainClass extends Sprite
                    public var content_txt:TextField;
                    public var posted_txt:TextField;
                    public var info_txt:TextField;
                    public var name_txt:TextField;
                    public var btnhome:MouseEvent;
  private static const USERNAME:String = "mytwitterid";
                    private static const URL:String = "http://pathtomyphp.com/proxy.php";
  private static const REQUEST:String = URL + USERNAME;
                    private var urlLoader:URLLoader;
                    private var xml:XML;
                    private var loader:Loader;
                    private var num:Number = 5;
                    public function MainClass() {
                              urlLoader = new URLLoader();
                              urlLoader.load(new URLRequest(REQUEST));
                              urlLoader.addEventListener(Event.COMPLETE, displayInfo);
                              urlLoader.addEventListener(SecurityErrorEvent.SECURITY_ERROR, onSecurity);
                    private function onSecurity(e:SecurityErrorEvent):void
                    private function displayInfo(e:Event):void
                              xml = new XML(e.target.data);
                              content_txt.htmlText = getContent(0) +  getContent(1) +  getContent(2)+ getContent(3);
                               info_txt.text = "Followers: " + xml.status[num].user.followers_count + "; " + "Following " + xml.status[num].user.friends_count + "; " + "Tweets " + xml.status[num].user.statuses_count + ";";
  name_txt.text = xml.status[num].user.screen_name;
  loader = new Loader();
                              loader.load(new URLRequest(xml.status[num].user.profile_image_url));
                              addChildAt(loader, 1);
                              loader.x = 116;
                              loader.y = 102;
                    private function getContent(num:Number) {
  var posted:String = xml.status[num].created_at;
                              var content:String = "<font color='#224466'><a href=" + '"http://twitter.com/' + USERNAME + "/statuses/" + xml.status[num].id + '" target="_blank">' + xml.status[num].text + "</a></font><br/><font size='9'>" +"Posted on: " + posted.substr(0, posted.length - 11) + "; " + "From: " + xml.status[num].source + "</font><br/><br/>";
  return content;
Like I said, on its own, it works great, just not when I try to create a new scene in an existing fla.
Thanks in advance for any advice you can give me.  I'm a little bit of an as3 newbie, so please bare with me . . .

Answer 1

I put MainClass in the same folder as the fla (it was in a subfolder in the same directory) and I still get the 1180 and 1046 errors.  Just to confirm, I have this in the first frame of the timeline:
var mc:MainClass=new MainClass();
addChild(mc);
and here is what I have for MainClass:
package fladev.twitter
          import flash.display.Loader;
          import flash.display.Sprite;
          import flash.display.MovieClip
          import flash.events.Event;
          import flash.events.SecurityErrorEvent;
          import flash.net.URLLoader;
          import flash.net.URLRequest;
          import flash.text.TextField;
       public class MainClass extends Sprite
                    public var content_txt:TextField;
                    public var posted_txt:TextField;
                    public var info_txt:TextField;
                    public var name_txt:TextField;
                    private static const USERNAME:String = "ctistechapps";
                    private static const URL:String = "http://preview.fladev.com/how-to-build-a-flash-actionscript-3-0-twitter-widget/proxy.php?u rl=";
                    private static const REQUEST:String = URL + USERNAME;
                    private var urlLoader:URLLoader;
                    private var xml:XML;
                    private var loader:Loader;
                    private var num:Number = 1;//display first post info, you can use also ?count=5
                    public function MainClass() {
                              urlLoader = new URLLoader();
                              urlLoader.load(new URLRequest(REQUEST));
                              urlLoader.addEventListener(Event.COMPLETE, displayInfo);
                              urlLoader.addEventListener(SecurityErrorEvent.SECURITY_ERROR, onSecurity);
                    private function onSecurity(e:SecurityErrorEvent):void
                    private function displayInfo(e:Event):void
            var _root:MovieClip = MovieClip(this.root);  // assuming you add this class instance to the main timeline before loading is complete.
            xml = new XML(e.target.data);                  
            _root.content_txt.htmlText = getContent(0) +  getContent(1)+ getContent(2) + getContent(3);  
            //trace(xml);
            //show some info about the user
            _root.info_txt.text = "Followers: " + xml.status[num].user.followers_count + "; " + "Following " + xml.status[num].user.friends_count + "; " + "Tweets " + xml.status[num].user.statuses_count + ";";
            //display the user account
            _root.name_txt.text = xml.status[num].user.screen_name;
            //create a loader for picture
            loader = new Loader();
            loader.load(new URLRequest(xml.status[num].user.profile_image_url));
            _root.addChildAt(loader, 1);
            loader.x = 116;
            loader.y = 102;
                    private function getContent(num:Number) {
                              //show just month, day and hour
                              var posted:String = xml.status[num].created_at;
                              var content:String = "<font color='#224466'><a href=" + '"http://twitter.com/' + USERNAME + "/statuses/" + xml.status[num].id + '" target="_blank">' + xml.status[num].text + "</a></font><br/><font size='9'>" +"Posted on: " + posted.substr(0, posted.length - 11) + "; " + "From: " + xml.status[num].source + "</font><br/><br/>";
                              //return all info
                              return content;