Ok, I finally got something working. I decided to work through the example in Dave Thomas' book 'Agile Web Development with Rails: A Pragmatic Guide'
(This book is not officially released until July 2005 but the authors have released a "beta" version in PDF format)
The example uses MySQL but I have translated the MySQL SQL code to Postgresql code.
This is the history of the commands I ran to create the sample depot app:
# cd /home/apache/robinbowes.com/rails
# rails depot
# chown -R apache:apache depot
# ln -s depot live
# cd depot/db
# vi create.mysql
# cp create.mysql create.pgsql
# vi create.pgsql
[created database and table using phpPgAdmin]
# cd ..
# vi config/database.yml
[Note: if the database config is not correct the scaffold generate fails]
# ruby script/generate scaffold Product Admin
Browse to http://rails.robinbowes.com/admin
Yey! It works!