After the initial question on this list about OGO and CentOS 4, here's what I've done.
I installed CentOS 4 on a qemu image and setup a yum repo pointing to download.opengroupware.org/packages/fedora-core3/releases/ . I did this based on the assumption that FC3 packages work on RHEL4/CentOS4.
yum install ogoall
With this command, OGO user and database was created (Postgresql was detected and used), database structure was uploaded to pgsql.
So far so good, http://localhost/OpenGroupware returns a 404.
service httpd restart
Same url, Apache Server Internal Error.
Ok, what's wrong?
system-config-services, the ogoall installation creates 4 new services, enables them as default but DOESN'T start them.
Upon starting those 4 services, http://localhost/OpenGroupware worked sucessfully, straight to OGO Administration.
I really didn't test it much, but, just by browsing some links on it, OGO seems to be working.
Best regards,
Pedro