Failing ODBC connection

Hello,

I am using pg 7.2.4 on a Linux host, and have recently written a
Perl/Perl:Tk application that works as expected when run from the local
host. Unfortunately, the proposed users are on Windows machines, and
when I try to run the same application there, I get the following error:

DBI connect('pg-gds2','HASH(0x1f03458)',...) failed: FATAL 1: user
"HASH(0x1f0
458)" does not exist
(SQL-28000)
[Microsoft][ODBC Driver Manager] The driver doesn't support the version
of ODBC
behavior that the application requested (see SQLSetEnvAttr).
(SQL-01000)(DBD: d
_login/SQLConnect err=-1) at C:\Perl\code\db_edit.pl line 200
Tk::Error: Can't connect to: FATAL 1: user "HASH(0x1f03458)" does not exist
(SQL-28000)
[Microsoft][ODBC Driver Manager] The driver doesn't support the version
of ODBC
behavior that the application requested (see SQLSetEnvAttr).
(SQL-01000)(DBD: d
_login/SQLConnect err=-1)
[\&main::bld_sql]
Tk callback for .button
Tk::__ANON__ at C:/Perl/site/lib/Tk.pm line 228
Tk::Button::butUp at C:/Perl/site/lib/Tk/Button.pm line 111
(command bound to event)

Relevant perl code is

$dbh = DBI->connect("dbi:ODBC:pg-gds2",{AutoCommit=>0}) or die "Can't
connect to: $DBI::errstr\n";

pg-gds2 is an ODBC DSN; the ODBC driver version is 7.2.5.
I also tried replacing the DSN with all the parameters
(driver,server,host,uid,pwid) on the call line with the same results.

Just for the sake of completeness, I can ping the server and telnet to
the server from the Windows machine, and pgadmin2 also works perfectly
(does it use ODBC?)

pg_hba.conf is: (not connected to outside world!)

# TYPE DATABASE IP_ADDRESS MASK AUTH_TYPE
AUTH_ARGUMENT

local all trust
host all 127.0.0.1 255.255.255.255 trust
host all 10.0.1.0 255.255.255.0 trust

The perl (and Tk and DBD/DBI) were just downloaded from ActiveState.

I am not terribly literate in Windows, much less ODBC, so any help is
appreciated.

Thank you very much,

Don