ActionScript 3.0 :: Adding Timestamp To XML File Address

I'm trying to add timestamp to the xml file address if the swf wil be loaded from the web server but it gives me a null object reference error depending on if there is timestamp() function call or not.

Here's my code that doesn't work as I was expecting:
ActionScript Code:
//...
public function init():void {
try {
xmlLoader = new URLLoader();
xmlLoader.addEventListener(IOErrorEvent.IO_ERROR, ioError);
[Code].....

When I load just addresses without the timestamp xmlLoader.load(new URLRequest(address)); it outputs everything I was already expecting when the timsetamp function call where involved, (as I was testing some considerable errors).
Code:
Class LoadXML/ address: start.xml
Class LoadXML/ address: play.xml
Class LoadXML/ address: end.xml
Class LoadXML/ io error: [IOErrorEvent type="ioError" bubbles=false cancelable=false eventPhase=2 text="Error #2032: Stream Error. URL: file:///E|/flash/as3/projectName/lib/work/end.xml"]