Pass variable as URL in getURL?

So I’ve loaded this XML data into my Flash file, and now that its there, I’m trying extract a URL from the XML data and pass it into a getURL function. Looks something like this:

on(release){
getURL(my_xml.firstChild.firstChild.nodeValue);
}

This construct doesn’t seem to be working, as I think it may have to do with the default (url, window, method) properties of the getURL function. The XML data located at my_xml.firstChild.firstChild.nodeValue is simply a URL (http://www.blahblahblah.com). Any ideas? Thanks!