Basic connection problem

I'm just trying to get going with an ODBC interface to Postgresql 8.1.5
on RHEL 3.0.  I'm using the database without problems via psql, ecpg,
and JDBC.

I've hit the same problem using both iODBC and unixODBC driver
managers.  It get the following when I try to connect to the database:

[08001][unixODBC]could not translate host name "port=5432" to address:
Name or service not known

[ISQL]ERROR: Could not SQLConnect

I've experimented with my ~/.odbc.ini file with and without Port = 5432
but can't seem to figure how port=5432 is even getting into the connect
string.

I've got psqlodbc 08.01.0200.  I had to make a couple of small coding
changes to build it for iODBC but unixODBC worked fine with  psqlodbc
code as downloaded.

I have unicode support turned on in the driver.  My database uses UTF8.

Surely this must be a common problem.  What am I doing wrong?

Paul