createdb errors and more

Today I restarted to install postgres from scratch, because I have a lot of installation problems. To summarize my system:
I have two xubuntu logins: a "superuser" and postgres. The latter one is a user with basic privileges.
I installed pgsql according to the manual, generated a data folder, changed ownership to postgres, switched user postgres and initialized the database. starting the database is also successful (status says running).
But now: when I use the command createdb test, I get the error "can't connect to database postgres: could not connect to server: no such file or directory, Is the server running locally and accepting .... etc."
When I switch user back to "superuser" I can start the server, add users etc. in pgAdmin3. But I need to be able to do this from the command line.
PLEASE help, I am getting really frustrated with this system, it already took me 2 weeks and still didn't get it right.

Another thing I can't get done: I created the postgresql init script in /etc/init.d/
When I reboot, the database is not automatically started. Do I need to login in the linux postgres account to let this happen? The database should also start in the background even when I login into another account?
Should the data dir only be owned by postgres or the entire /usr/local/pgsql dir??

Again, hopefully somebody can push me in the right direction.

Thanks, reno

**************************************************************************************************
This email and any attachments may contain confidential or privileged
information and is intended for the addressee only. If you are not the
intended recipient, please immediately notify us by email or telephone and
delete the original email and attachments without using, disseminating or
reproducing its contents to anyone other than the intended recipient. The
azM shall not be liable for the incorrect or incomplete transmission of this
email or any attachments, nor for unauthorized use by its employees.
**************************************************************************************************