NoMethodError: undefined method `fformat' - rake aborted!

Hello,

I have installed postgresql 8.3 in linux Mint 6 r1 (ubuntu 8.10) and the
ruby from ubuntu repositories, then "gem install rails -y"

I've installed "gem -install postgres-pr -y" and configured the
database.yml as follows:

database.yml

Sorry, I've forgotten to say that I've tried to issue manually those
queries that postgresql_adapter.rb does, and jere are the results, just
in case that could help:

postgresql_adapter.rb (line 251):

      query('SHOW standard_conforming_strings')[0][0] => 'off'

postgresql_adapter.rb (line 605):

      query('SHOW client_min_messages')[0][0] => 'notice'