Unfortunately "alter user nsadmin createuser" doesn't appear to grant the superuser permission to the user. However, if the user is already a superuser and you remove the permission that works really great!
The need for this privilege will go away when running PG 7.2, at some point.
What you need to do is to pg_dump your database, drop the database and user, recreate the user with the superuser privilege, load acs-kernel/sql/postgresql.sql, then reload your data.
I suggest trying this on a test system before dropping your database and data, though.
You'll get some duplicate function definition errors when you reload but these are safely ignored.
