FIXED : #282 : problem converting docx to pdf

PHP Catchable fatal error: Argument 2 passed to DOMXPath::query() must be an instance of DOMNode, null given, called in /var/www/xxx/PhpWord/Reader/Word2007.php on line 145 and defined in /var/www/xxx/PhpWord/Shared/XMLReader.php on line 99, referer: XXX