XML loading problem

programming flash
1

hello
here’s a simple problem for you. I have a XML file:

<q1>
    <q>question</q>
	<a>a1</q>
	<b>a2</q>
	<c>a3</q>
	<d>a4</q>
</q1>

I tried to trace it like this but I’m facing an “undefined” output:

var my_xml = new XML();
my_xml.onLoad = function(success){
	if (success){
		
        var test=my_xml.firstChild.childNodes;
        trace(test[0]);
	}
	else{
		trace("err");
	}
}
my_xml.load("q.xml");

what’s the problem?
my_xml.firstChild.childNodes is “<q1> and then <q>” right?

thx for your time.

edit:I’m using CS4,AS2 compiler. But I can even test it on Flash 8.