While experimenting with DBI and my PostgreSQL database I
stumbled upon this:

irb(main):003:0> aResult = aConnection.select_all("select * from pg_class")
DBI::InterfaceError: Unsupported Type (typeid=1034)
	from /usr/local/stow/ruby/lib/ruby/site_ruby/1.6/DBD/Pg/Pg.rb:265:in `convert'
	from /usr/local/stow/ruby/lib/ruby/site_ruby/1.6/DBD/Pg/Pg.rb:484:in `fill_array'
	from /usr/local/stow/ruby/lib/ruby/site_ruby/1.6/DBD/Pg/Pg.rb:483:in `each_with_index'
	from /usr/local/stow/ruby/lib/ruby/site_ruby/1.6/DBD/Pg/Pg.rb:483:in `each'
	from /usr/local/stow/ruby/lib/ruby/site_ruby/1.6/DBD/Pg/Pg.rb:483:in `each_with_index'
	from /usr/local/stow/ruby/lib/ruby/site_ruby/1.6/DBD/Pg/Pg.rb:483:in `fill_array'
	from /usr/local/stow/ruby/lib/ruby/site_ruby/1.6/DBD/Pg/Pg.rb:465:in `fetchrow'
	from /usr/local/stow/ruby/lib/ruby/site_ruby/1.6/DBD/Pg/Pg.rb:421:in `fetch'
	from /usr/local/stow/ruby/lib/ruby/site_ruby/1.6/dbi/dbi.rb:1058:in `fetch_all'
	from /usr/local/stow/ruby/lib/ruby/site_ruby/1.6/dbi/dbi.rb:1058:in `loop'
	from /usr/local/stow/ruby/lib/ruby/site_ruby/1.6/dbi/dbi.rb:1058:in `fetch_all'
	from /usr/local/stow/ruby/lib/ruby/site_ruby/1.6/dbi/dbi.rb:831:in `fetch_all'
	from /usr/local/stow/ruby/lib/ruby/site_ruby/1.6/dbi/dbi.rb:588:in `select_all'
	from /usr/local/stow/ruby/lib/ruby/site_ruby/1.6/dbi/dbi.rb:584:in `execute'
	from /usr/local/stow/ruby/lib/ruby/site_ruby/1.6/dbi/dbi.rb:584:in `select_all'
	from (irb):3

Looks like DBD/Pg has some problems with the table.

Cheers
Martin