Mac and PC paths

Hi
Could anyone help with this small problem? Am using AIR to create a very simple app and am testing on pc and Mac. The PC side works flawlessly but on the Mac get stream errors and file not found though the path and file and traced ok.

<code>
var XML_URL:String = File.userDirectory.nativePath;
var Platform:String;
Platform = Capabilities.os;
if ( Platform.substr(0,1) == “W”)
{
XML_URL +="[\Test\ est.xml](file://\Test\ est.xml)";
}
else
{
XML_URL +="/Test/test.xml";
}

trace(“XML”,XML_URL);
myXMLURL = new URLRequest(XML_URL);
myLoader = new URLLoader(myXMLURL);
myLoader.addEventListener(“complete”,xmlLoaded);
</code>