Creating users in a second postgres server.

Hi..

I have a Solaris 2.8 machine on which I have Postgresql 7.2.4 postgres
listening on port 5432. This works fine.

I have a user who needs a newer version and has asked specifically for
7.3. I have compiled and installed a 7.3.4
successfully, using
./configure --prefix=/usr/local/p_sql734 --with-pg_port=5433

I created a new os user, p_sql734, group postgres (same group as the
7.2.4) and initdb works fine.
pg_ctl start shows the following output
bash-2.03$ more p_sql734.log
LOG: database system was shut down at 2003-11-05 10:23:33 WET
LOG: checkpoint record is at 0/83B238
LOG: redo record is at 0/83B238; undo record is at 0/0; shutdown TRUE
LOG: next transaction id: 480; next oid: 16976
LOG: database system is ready

which seems to indicate that everything is fine.

The processes are alive

ps -ef |grep post
p_sql734 26503 26502 0 10:25:44 ? 0:00
/usr/local/p_sql734/bin/postmaster
postgres 27012 26760 0 10:36:26 pts/1 0:00 -bash
postgres 27386 27385 0 Oct 22 ? 0:01
/usr/local/pgsql/bin/postmaster
p_sql734 26502 26501 0 10:25:44 ? 0:00
/usr/local/p_sql734/bin/postmaster
postgres 27383 1 0 Oct 22 ? 0:02
/usr/local/pgsql/bin/postmaster
postgres 27385 27383 0 Oct 22 ? 0:00
/usr/local/pgsql/bin/postmaster
p_sql734 26501 1 0 10:25:44 ? 0:00
/usr/local/p_sql734/bin/postmaster
postgres 27231 27012 0 10:39:45 pts/1 0:00 -bash

however, when I try and create a user I get
bash-2.03$ createuser idip_734
Shall the new user be allowed to create databases? (y/n) y
Shall the new user be allowed to create more new users? (y/n) n
psql: FATAL 1: user "p_sql734" does not exist
createuser: creation of user "idip_734" failed

I tried the same thing with p_sql734 (though I don't remember having had
to create the owner in the database before) and got the same message

bash-2.03$ id
uid=122(p_sql734) gid=202(postgres)
bash-2.03$ createuser p_sql734
Shall the new user be allowed to create databases? (y/n) y
Shall the new user be allowed to create more new users? (y/n) y
psql: FATAL 1: user "p_sql734" does not exist
createuser: creation of user "p_sql734" failed

I've edited ${PGDATA}/postgresql.conf and set port=5433 to make sure
that I'm on the correct port.

I'm sure Ive missed something fairly basic but I can't find it.

Any ideas?

Thanks

Stephen.