I have a web server set up on my laptop. I am building a web application which I am accessing through the local network. I have a php file which contains the following lines
OpenOffice needs a user directory. Since you are trying to invoke OpenOffice with the web server, you have to grant the respective user write access to is. On Debian, for instance, that would mean to allow www-data to write to /var/www/.openoffice.org/:
mkdir /var/www/.openoffice.org
chown www-data /var/www/.openoffice.org