HP/Pgsql/DBD::Pg issue

After a reboot (and usually after an OS patch) on our HP-UX 11.23
64-bit Itanium DB servers, our libpq/DBD::Pg libraries cease to
work.  Instead, they give the standard message you get when the
DB cluster is not running.  But we *know* it is running and all
access paths are working.  We have found a workaround by
switching from 64-bit perl to 32-bit perl, build a 32-bit pgsql,
and rebuild the perl DBD module using 32-bit perl and linking
with the 32-bit pgsql.  But the fact we're having to do that is
a problem for us.

I don't understand this problem and am at a loss as to where to
look.  Any ideas?

TIA.

Ed