FCKeditor v2.5 problem with firefox 2.0 using php

 67FCKXml.prototype={LoadUrl:function(A){this.Error=false;var B=this;var C=FCKTools.CreateXmlObject('XmlHttp');C.open("GET",A,false);C.send(null);if (C.status==200||C.status==304) this.DOMDocument=C.responseXML;else if (C.status==0&&C.readyState==4) this.DOMDocument=C.responseXML;else this.DOMDocument=null;if (this.DOMDocument==null||this.DOMDocument.firstChild==null){this.Error=true;if (window.confirm('Error loading "'+A+'"\r\nDo you want to see more info?')) alert('URL requested: "'+A+'"\r\nServer response:\r\nStatus: '+C.status+'\r\nResponse text:\r\n'+C.responseText);}},SelectNodes:function(A,B){if (this.Error) return [];var C=[];var D=this.DOMDocument.evaluate(A,B?B:this.DOMDocument,this.DOMDocument.createNSResolver(this.DOMDocument.documentElement),XPathResult.ORDERED_NODE_ITERATOR_TYPE,null);if (D){var E=D.iterateNext();while(E){C[C.length]=E;E=D.iterateNext();}};return C;},SelectSingleNode:function(A,B){if (this.Error) return null;var C=this.DOMDocument.evaluate(A,B?B:this.DOMDocument,this.DOMDocument.createNSResolver(this.DOMDocument.documentElement),9,null);if (C&&C.singleNodeValue) return C.singleNodeValue;else return null;}};