pam 'Conversation failure' under Solaris

Hi,

I am trying to get postgres 7.3.2 to work with pam under Solaris 2.7.
The only option I gave to ./configure (apart from --prefix) was
--with-pam.

This is the matching line from my pg_hba.conf file:
host all all xxx.xx.xx.xx 255.255.255.255 pam other

and here are the relevant lines from /etc/pam.conf

other auth required /usr/lib/security/pam_unix.so.1
other account required /usr/lib/security/pam_unix.so.1
other session required /usr/lib/security/pam_unix.so.1
other password required /usr/lib/security/pam_unix.so.1

When I try and connect from a remote client (psql), postgres immediately logs
this:

LOG: CheckPAMAuth: pam_authenticate failed: 'Conversation failure'
FATAL: PAM authentication failed for user "ucactgj"

and syslog logs this:

green postgres[21528]: pam_authenticate: error Conversation failure

The client then asks for my password. When I hit return, postgres
logs this:

LOG: CheckPAMAuth: pam_authenticate failed: 'Authentication failed'
FATAL: PAM authentication failed for user "ucactgj"

and syslog logs this:

green postgres[21961]: pam_authenticate: error Authentication failed

When trying to connect over the unix socket on the localhost, I
get similar messages, with the addition of postgres logging this
(before the password is entered):

LOG: pq_flush: send() failed: Broken pipe

The only similar thing I can find in the archives is at this URL:
http://archives.postgresql.org/pgsql-admin/2002-06/msg00110.php
but that message got no reply.

Does anyone actually have postgres working with pam under solaris?

cheers,
Tom.