FATAL cannot create init file... why?

Hello all,
I am using Red Hat linux v7.0 which installs postgreSQL.
I have been learning how to use it for the last three days while reading
Bruce Momjian's excellent book - postgreSQL introduction and concepts.
I had no problems until yesterday.
I typed:
psql test
to connect to my test database and got:
FATAL 1: cannot create init file ./data/base/test/pg_internal.init.1352

This used to work fine. The only unusual thing that I did the previous day
was to run pgaccess. The only change I made to the system was to edit my
/etc/hosts file to get pgaccess working. I have made no other changes to the
system for the last few days. I am at a loss.

I hope you can help.