[melky]

заменить

if (req.responseXML != null)
                        {
                                gtable = req.responseXML.getElementsbyTagName('table');
                                getTable(gtable);
                        }

на

var a = document.createElement("div");
                                a.innerHTML = req.responseText;
                                gtable = a.getElementsbyTagName('table');
                                getTable(gtable);