could not bind IPv4 socket

Hi all,

I installed postgresql 8.3.5 with these commands:
- ./configure --enable-thread-safety (I need this because of dbt2)
- make
- make install

I executed initdb. It's ok. I changed "postgresql.conf" file:
listen_addresses = '*'.
So, when I started postgresql, I receive these messages:

$ pg_ctl start
server starting
$* LOG: could not bind IPv4 socket: Address already in use
HINT: Is another postmaster already running on port 5432? If not, wait a
few seconds and retry.*
LOG: database system was shut down at 2009-03-18 11:32:55 BRT
LOG: autovacuum launcher started
LOG: database system is ready to accept connections

What's wrong? Why do I receive these messages (about IPv4 socket and HINT)?
Can you help me?

Thanks,
Ana Carolina