System Administrator's Guide/Enabling Plpgsql
If you are using an old version of Postgres (8.1 or 8.2), and you are installing or upgrading to Mahara 1.5, you will need to ensure the plpgsql language is available in your Mahara database. The following commands can be used in your psql database client:
CREATE TRUSTED LANGUAGE plpgsql; GRANT USAGE ON LANGUAGE plpgsql TO <mahara_db_user>;
Replace <mahara_db_user> with the user that mahara connects to the db with.
(Works on Red Hat Enterprise Linux 5.8, PostgreSQL 8.1.23)