AutoCAD Map 3D :: Connection Failure To PostgreSQL / Postgis (Linux Host)

I would like to connect a Map3D drawing to a PostgreSQL/PostGIS database hosted on a linux server on my network.  In the past I have successfully connected to PostgreSQL/PostGIS when the server/db is running on the same Windows box where I am using AutoCAD.  I've been able to do this with several combinations of Windows (XP/7/7x64)/PostgreSQL(8.4/9.1)/PostGIS (1.5/2.0) and AutoCAD Map (2013). 

I have even been able to connect from one Windows PC running AutoCAD Map to a PostGIS database hosted on another Windows machine on the network, but not to a database hosted by a Linux server.  When I try this from an XP workstation, the application (ACAD) immediately crashes without warning (this happens after I enter the connection information and try to "login").  On Windows 7, the application crash is almost as immediate, but it at least gives me an exit code error "FATAL ERROR: Unhandled e06d7363h Exception at..."

I've tried to view the postgres logs on the db server.  I usually get one of these for each failure:

2013-05-31 10:53:42 EDT LOG:  could not accept SSL connection: Connection reset by peer

I've tweaked the postgres file (pg_hba.conf) to allow non-ssl/ssl/etc to make sure that I don't have problems there.  In fact, I have other GIS apps on the AutoCAD workstation that I use to test the PostGIS connectivity prior to trying AutoCAD.  I've looked for other things like Antivirus/firewall that might be contributing, but I've come up empty.  I've also tried using the newer "OGR FDO" providers from osgeo.org.  I get the same behavior with those.

In short, how to be able to connect AutoCAD Map 3D 2013 to a non-Windows PostgreSQL/PostGIS host? How to get a successful connection.