I built a simple portfolio interface with button instances in Flash CS5, using ActionScript3.0, designed to load and unload external SWFs. In CS5, everything functions properly and there are no errors. However, when I open the file in CS5.5, nothing works. Here is my ActionScript:

var myLoader:Loader=new Loader ();

myLoader.x=0;

myLoader.y=235;

button1.addEventListener(MouseEvent.CLICK, button1content);

function button1content(myevent:MouseEvent):void {

          var myURL:URLRequest=new URLRequest("button1.swf");

          myLoader.load(myURL);

          addChild(myLoader);

}

button2.addEventListener(MouseEvent.CLICK, button2content);

function button2content(myevent:MouseEvent):void {

          var myURL:URLRequest=new URLRequest("button2.swf");

          myLoader.load(myURL);

          addChild(myLoader);

}

button3.addEventListener(MouseEvent.CLICK, button3content);

function button3content(myevent:MouseEvent):void {

          var myURL:URLRequest=new URLRequest("button3.swf");

          myLoader.load(myURL);

          addChild(myLoader);

}

button4.addEventListener(MouseEvent.CLICK, button4content);

function button4content(myevent:MouseEvent):void {

          var myURL:URLRequest=new URLRequest("button4.swf");

          myLoader.load(myURL);

          addChild(myLoader);

}

button5.addEventListener(MouseEvent.CLICK, button5content);

function button5content(myevent:MouseEvent):void {

          var myURL:URLRequest=new URLRequest("button5.swf");

          myLoader.load(myURL);

          addChild(myLoader);

}

My professor said that my actionscript is correct. All external SWFs are located and properly named in the same folder as the interface file, with nothing else. Can anyone explain this problem?