A friend contacted me the other day because he was having an issue starting his development environment which consists of Ruby, PostgreSQL, and Mongrel. Ruby communicates with PostgreSQL using the postgres-pr gem version 0.6.1. Starting things using “ruby script/server” from within his Ruby project had been working for months without issue and there had been no confguration changes to Ruby, Postgres, or Mongrel so it appeared to not be configuration related. After getting a brief explanation of the issue I logged into his laptop and attempted to start the server. Below is the error received when attempting to start the server using “ruby script/server” via a terminal window on the Macbook Pro.