Hello,
As you check on the readme, we recommend to use OpenOffice because LibreOffice has some issues running on headless mode.
As you're already running OpenOffice:
[root@kvm85 ~]# ps aux | grep soffice
root 1280 0.0 0.1 106060 1388 pts/0 S+ 09:11 0:00 /bin/sh /opt/openoffice4/program/soffice -headless -accept=socket,host=127.0.0.1,port=8100;urp; -nofirststartwizard
root 1289 0.0 5.6 609800 57364 pts/0 Sl+ 09:11 0:00 /opt/openoffice4/program/soffice.bin -headless -accept=socket,host=127.0.0.1,port=8100;urp; -nofirststartwizard
root 1338 0.0 0.0 103244 832 pts/1 R+ 09:18 0:00 grep soffice
run the included example, advanced/Transform.php, using the CLI mode:
$ php Transform.php
Enablig the debug mode and post the output. Please check that SELinux or a firewall aren't blocking the access to OpenOffice.
Regards.