stream error creating new xml

I have a local xml file which contains some properties used to connect to a server.

This file is stored in the app-storage. But if this file doesn't exist yet, it needs to be created.

At that moment I get following stream error (popped up by the method showAlert):

Server.Error.Request – HTTP request error - Error: [IOErrorEvent type="ioError" bubbles=false cancelable=false eventPhase=2 text="Error #2032: Stream Error. URL: app:/Server.xml" errorID=2032]. URL: Server.xml

And this is my code:

publicfunction loadSavedConfig():void{

var settingsFile:File = File.userDirectory.resolvePath("app-storage:/Server.xml");

      var serviceData:HTTPService =  new HTTPService();

      if (settingsFile.exists == false) {

            serviceData.url = "Server.xml";

            serviceData.addEventListener("result",  function(event:ResultEvent):void {serverDataLoadedLocally(event.result);});

            serviceData.addEventListener(FaultEvent.FAULT, showAlert);

            serviceData.send();

      } else {

            serviceData.url = settingsFile.url;

            serviceData.addEventListener("result",  function(event:ResultEvent):void {serverDataLoadedLocally(event.result);});

            serviceData.send();

      }                      

}

Does anyone has an idea what I'm doing wrong?

Thanks in advance.

Regards.

Kristof