Scripts working fine on my machine but error: object required , on older desktop

[freefony]

i built a shopping software for a customer its working perfectly on my system but when i transferred to my customer's old desktop system this script throws error "object required" i tried Flock browser no error but no output here is my script below

   if (req.status==200) { 
				  
                    xmlResponse = req.responseXML; 
					xmlElement  = xmlResponse.documentElement;
					//alert( xmlElement.childNodes[3].childNodes[0].data)
					if( xmlElement.firstChild.childNodes[0].data =="Successful"){
						
						if(document.getElementById(src).innerHTML ==""){
						
						document.getElementById(src).innerHTML += "<table width='100%' border='1' cellspacing='0' bordercolor='#999999'><tr bgcolor='#EAEAEA'><td width='10%'>REMOVE</td><td width='50%'>ITEM NAME</td><td width='10%'>QUANTITY</td><td>PRICE</td></tr></table>";
						}
						totp = parseFloat(totp) + parseFloat(xmlElement.childNodes[4].childNodes[0].data)
						rw = "<div id='item"+row+"'>";
						rw += "<table width='100%' border='1' cellspacing='0' bordercolor='#ffffff'><tr bgcolor='#EAEAEA'>";
						rw += "<td width='10%'><a href=javascript:removeRow('item"+row+"','"+ xmlElement.childNodes[1].childNodes[0].data +"','"+rno+"','"+branch+"','"+  xmlElement.childNodes[3].childNodes[0].data +"','"+ xmlElement.childNodes[4].childNodes[0].data +"')>REMOVE</a></td><td width='50%'>"+  xmlElement.childNodes[2].childNodes[0].data +"</td><td width='10%'>"+  xmlElement.childNodes[3].childNodes[0].data +"</td><td>"+ xmlElement.childNodes[4].childNodes[0].data +"</td></tr></table></div>";
						
}

could it be that this machine does not support XML ? i ve tried 4 browsers on my system and they all worked(IE,Safar i,Opera,Firefox )

[acoder]

Which line is the error on and which browser and version number are using on the customer's machine?