Hello,
Please check your phpdocxconfig.ini, it seems the default INI structure [transform] is missing. Enable the method and path options removing the ';' of feach line. and set its values.
Also note that the third parameter of transformDocument is the temp folder, not the option parameters that is an array.
http://www.phpdocx.com/api-documentation/format-conversion/convert-Word-docx-into-pdf-with-PHP
Regards.