What am I doing wrong with pg_hba.conf? I'm trying to make it so that local connections to the database don't require a login. So I added the line local    all   all    trust to the pg_hba.conf file, but then when I load pgAdmin and try to connect to the server it just says FATAL: could not load pg_hba.conf. What am I doing wrong?
There is likely an invalid entry in pg_hba.conf file. Reload it and then check the PostgreSQL server log for any pg_hba.conf error:

pg_ctl reload -D $PGDATA