Createdb fails

I am trying to use PostgreSQL 7.2.1 on QNX 6.2.0. This version is
available as a third party package from QNX.

After installing the package, I am trying to initialize the database as
described in the Administrator Manual.

http://www.postgresql.org/docs/7.2/interactive/installation.html#INSTALL
-SHORT

I started postmaster using the following command:

postmaster -D /var/postgres/data >>logfile 2>&1 &

I have verified that postmaster is running by using "ps".

I then try to create a database using the following command:

createdb test

and I get the following error:

psql: could not connect to server: Connection refused
Is the server running locally and accepting
connections on Unix domain socket ""?
createdb: database creation failed

The odd thing that I notice is that the socket is null (i.e. ""). Is
this expected? Anyone know what I am doing wrong?

...Stephen