Postgres set up problem

[beamends <..hidden..>]

Ok, I'm starting to get somewhere but this has now cropped up. I've
installed postgreql8.2  but :

..hidden..:~$ createuser --no-superuser --createdb
--no-createrole -U postgres --pwprompt --encrypted ledgersmb


produces :

createuser: could not connect to database postgres: FATAL:  Ident
authentication failed for user "postgres"

Hunting round I'd found that etc/postgresql/8.2/main.postgresql.conf
contained :
port = 5433 # (change requires restart)

which generated a createuser error similar to the above but queried the
unix socket

/var/run/postgresql   had files .s.PGSQL.5433  and .s.PGSQL.5433.lock

in it, but changing etc/postgresql/8.2/main.postgresql.conf to 
...5432 doesn't create  .s.PGSQL.5432  and .s.PGSQL.5432.lock

Presumably that's my problem?

Cheers
Richard