[ODBC] Windows NT, ODBC 3.x, problem to connect

Hello folks,

after upgrading to PostgreSQL and PostODBC and Microsoft ODBC to the latest
versions I cannot connect to Postgres anymore.

Versions:
backend:  PostgreSQL 6.3.2
          Linux 2.0.30
          172.16.5.12
user:          PostgreSQL 6.30.0245
          WinNT WS 4.0 SP3
          ODBC 3.5
          172.16.4.233

error message:
When i try to create a query (MS-Query) i get the error message:
"Could not connect to the server;
 Could not connect to the remote socket."

When I connect via telnet to the server and use psql I can access the
requested database w/o problem.
The pg_hba.conf looks like this:
-----start-----
# first attempt
# allow all hosts from 172.16.4.x access to database test1
host    test1   172.16.4.0      255.255.255.0   trust

# second attempt
# allow workstation orion access to all databases
host    all     172.16.4.233    255.255.255.255 trust

# desperately seeking connection... in the third attempt
host    all     0.0.0.0         0.0.0.0         trust
host    all                                     trust
-----end-----

any ideas?

Thnx

Matthias