Please download the latest version of phpdocx, that uses a new version of openoffice.
To use plugin conversion you can use any version of openoffice (3.2 or greater): included one in phpdocx package or your custom install (Windows, Mac or Linux). The version included within phpdocx is for 32bits machines, so if you have a 64 bits distro you need to install the ia32 package (ia32-libs).
After you have openoffice installed or copied, init it in headless mode (using a script or a command). Now you can instanciate CreateDocx or TransformDocxAdv classes to do transformations.
The next version of phpdocx will include a more detailed guide about this plugin and several improvements.