Databases must be registered in the openoffice registry of user oomailing

The easy way to do that is to lunch openoffice as oomailing:

As root, set a password:
host:~# passwd oomailing

Then login with an X display:
user@host:~$ ssh -X oomaling@localhost

Lunch openoffice
oomailing@host:~$ soffice

If necessary, load sdbc-postgres driver, using Tools/Package Manager from the menu, then click on "Add" and select postgres-sdbc-0.7.5.zip that you've downloaded from http://dba.openoffice.org/drivers/postgresql/index.html
On modern distro, you might prefer to install the package:
host:~# apt-get install openoffice.org-sdbc-postgresql

You need to restart openoffice after that. Also restart oomailing server:
host:~# /etc/init.d/oomailing restart

You might need to register databases. Launch openoffice again:
oomailing@host:~$ oowriter
Then choose Edit/Select Database from the menu. Here you can add a database, such as /var/www/guideogm/static/guideogm.odb