Odd permission denied message when starting client

I have just installed Postgresql 7.3.4 on my slackware 9.1 system.
The installation went fairly smoothly and the server process has
started normally:-

postgres 21027 20767 0 20:12 pts/5 00:00:00 -su
postgres 21246 1 0 20:17 pts/3 00:00:00 /usr/bin/postmaster -D /var/lib/postgresql/data
postgres 21248 21246 0 20:17 pts/3 00:00:00 postgres: stats buffer process
postgres 21251 21248 0 20:17 pts/3 00:00:00 postgres: stats collector process

However when I try and run a postgres client process as an ordinary
user I get the following:-

FATAL: could not open configuration file "postgresql.conf": Permission denied

As I understand it the permissions on the postgresql data directory
should be 0700 and owned by the postgresql user and this is how they
are set. So what permission(s) is this error complaining about?

--
Chris Green (chris(at)areti(dot)co(dot)uk)

"Never ascribe to malice, that which can be explained by incompetence."