This is a fantastic script. Easy to implement and works well. However on our linux server we had a problem with the use of php sys_get_temp_dir() in the createDocx class in which $this->_tempFile was coming back empty. Easily solved by inserting our own temp file solution.
I notice at php.net (http://php.net/manual/en/function.sys-get-temp-dir.php) there are one or two comments regarding this:
This function does not account for virtualhost-specific modifications to the temp path and/or open_basedir.
Maybe a different implementation to that in the class would cover more server configs..