Reading XML file from HTTP

Hi everyone,
I'm finding an issue with the objects involving ain a routine i am cerating for reading an XMl file from an HTTP request. here is the part of the code:

IF ISCLEAR(locautXmlDoc) THEN
   CREATE(locautXmlDoc,FALSE,TRUE);
locautXmlDoc.load(XMLHTTP.responseXML);
CREATE(xmlNodeList, FALSE, TRUE);
xmlNodeList := locautXmlDoc.getElementsByTagName('CONNUMBER');

The code fails when it tries to create the xmlNodeList variable, with this error:

Cannot create an instance for the automation server with CLSIF ={XXX-XXXX}

I have to say that the HTTP call has a response, that can be seen with the Fiddler (courtesy of @Slawek_Guzek )

<?xml version="1.0" encoding="UTF-8" standalone="yes"?><document><CREATE><CONREF>15D</CONREF><CONNUMBER>GE158487071ES</CONNUMBER><SUCCESS>Y</SUCCESS></CREATE></document>

What I'm doing wrong in the creation of the NodeList?
Thank you very much