[KiL33]

Так...?

var myContent:XML = new XML();
var contentURL:String = "numb.xml";
myContent.onLoad = function(success) {
	if (success) {
		var contentURL:Number = 0;
		btn.onPress = function() {
			if (contentURL == undefined) {
			} else {
				contentURL++;
			}
			mdm.FileSystem.saveFileUnicode("numb.xml",contentURL);
			trace("!!_"+contentURL);
		};
	}
};
myContent.load(contentURL);

Эффект тот же(((