xmldoc issue

Hi all , I have two server . In first server , which PHP version 4.3.2, the code below is ok : function validatexmlfile($xmlfilename)

    {
        $_logger = new Log4jLogger();
        $_logger->logdebug("starting validate xml");
        $_logger->logdebug("starting validate xml xmlfilename:",$xmlfilename);

        if (!$doc = xmldocfile($xmlfilename)) {
            die("Error in XML");
            $this->xml_error = TRUE;
        }
        // version check
        else if ($doc->version > 1.0) {
            die("Unsupported XML version");
            $this->xml_error = TRUE;
        } else {
            $this->xml_error = FALSE;
        }

However in second server , it did not get past the xmldocfile() at all. Anybody have any ideas what is happening ? I have set the error_reporting to E_ALL , but it did not display any error at all. Thanks