Two configuration issues...

I have Postgres 8.1 on Kubuntu Breezy on powerpc. I used the apt-get
to install the package. The server ran fine right from the beginning
and I had no problems with psql. I then changed the location of my
data directory and I created a new user. I can still use psql, but
now I have two (maybe small) issues.

1. When I attempt /etc/init.d/postgresql-8.1 restart I get the error:

Stopping PostgreSQL 8.1 database server: main
Error: pid file is invalid, please manually kill the stale server process

...but the server starts up just fine. When I look at current process
I find four postmaster processes. I don't really know how to describe
it, but it looks like one lead process, two sub-processes, and one
sub-sub-process. Is this a problem? Did I forget to do something
when changing my data directory?

2. My other problem: When I am running as a non-root user and I type:
$ su postgres
I'm asked for a password and no matter what I type I have an
authorization failure. Now, I assumed this would be the password I
created for my superuser when running initdb -D. Is there anyway to
figure out what this password is or to change it? Or do I need to
just accept that I need to do su root before I do su postgres?

Thanks for any help or suggestions.

-eric