XML Problem

1

I have the following code in the main timeline:

var My_XML:XML = new XML(); 
var rootXML1;
My_XML.ignoreWhite = true; 
My_XML.onLoad = function(success:Boolean){ 
   rootXML1 = this.childNodes; 
   trace(this.status); 
   if (success){ 
      trace (this.firstChild.firstChild); 
   } else { 
      trace ("fail"); 
   } 
} 
My_XML.load(_global.fileName); 

trace(rootXML1.firstChild.firstChild);

The trace on line 8 works perfectly.
However, the final trace does not.

Could anyone tell me how to make the final trace statement work?

Cheers,

David