Remote / network connection fails

Dear list,
I am trying to connect to my database over the network. When trying to connect to the
server from a Windows client via psql with

#-> psql -h pg_server_ip -d postgres -U postgres OR
#-> psql -h pg_server_ip -d cms -U cmsuser

I get the following error (same with pgAdmin3)

psql: could not connect to server: Connection refused (0x0000274D/10061)
Is the server running on host "pg_server_ip" and accepting
TCP/IP connections on port 5432?

****
- I am using PostgreSQL 8.3 on Debian Etch.
- The server is up and running on host "pg_server_ip" on Port 5432.
- The Postgres server process is running as UNIX user 'postgres'.
- I can connect to the postgres-server locally via PSQL.
- A CMS is running fine with a Postgres data base 'cms' as backend on the same machine.
- I changed 'listen_address' to '*' in postgresql.conf
- iptables allows connections on ports 22, 80 and 5432.
- pg_hba.conf looks as follows:

# LOCAL CONNECTIONS
local all postgres ident sameuser
local all cmsuser md5
local all all ident sameuser

# IPv4
# TYPE DBASE USER CIDR-ADDRESS METHOD [OPTION]
host all all 131.220.0.0/16 md5
host all all 127.0.0.1/32 md5

- I restarted the Postgres server process / reloaded the config files after modification.

Since the CMS with 'cmsuser' is running fine, I suspect it is connecting locally. What do
I have to change at the IPv4 connections?

Thanks in advance,
Nils