Question about addRow process

[jerseysal]

I have added fields to the code to support my application. When I try to add a row, the functions work but the new row is not visible on the grid. I see this message in my console:

Could not load XML from url 'php/loaddata.php' which is generated by this function, below. My question is what is wrong? Where/What should I look for to fix this? The reference to "ReadyState 4" is a tad cryptic. Perhaps an enum could be used with a tad more description? Jus' sayin'... Any wisdom would be greatly appreciated..

The "url" referenced is php/loaddata.php.

EditableGrid.prototype.loadXML = function(url, callback, dataOnly)
{
this.lastURL = url;
var self = this;

// IE
if (window.ActiveXObject)
{
	this.xmlDoc = new ActiveXObject("Microsoft.XMLDOM");
	this.xmlDoc.onreadystatechange = function() {
		if (self.xmlDoc.readyState == 4) {
			self.processXML();
			self._callback('xml', callback);
		}
	};
	this.xmlDoc.load(this._addUrlParameters(url, dataOnly));
}

// generic Ajax
else if (window.XMLHttpRequest)
{

	this.xmlDoc = new XMLHttpRequest();
	this.xmlDoc.onreadystatechange = function () {
		if (this.readyState == 4) {
			self.xmlDoc = this.responseXML;
			if (!self.xmlDoc) { console.error("Could not load XML from url '" + url + "'"); return false; }
			self.processXML();
			self._callback('xml', callback);
		}