backend closed the channel unexpectedly

We have a system developed on PostgreSQL 7.1 on a Mac OS X 10.1
(FreeBSD) system -- which works well there.  Now we're trying to port
the code to another box, running RedHat Linux 6.2 -- which has
PostgresSQL already installed:

    PostgreSQL 6.5.3 on i686-pc-linux-gnu, compiled by gcc egcs-2.91.66

Several files defining PL/pqSQL stored procedures need to be loaded, but
the "psql" command interpreter dies part way through loading with the
error message:

-----

pqReadData() -- backend closed the channel unexpectedly.
         This probably means the backend terminated abnormally
         before or while processing the request.
We have lost the connection to the backend, so further processing is
impossible.  Terminating.

----

If the files are split into smaller parts, one can keep loading stored
procedures (Oracle 8.0.5.1 had a bug like that...) but "psql" still dies
with the same error after each successive procedure is loaded.

For what it's worth, the database server is launched from RedHat's
script "/etc/rc.d/init.d/postgresql" via the line:

    su -l postgres -c '/usr/bin/postmaster -i -S -D/var/lib/pgsql'

Are we breaking some kind of limit on stored procedure definitions?  I'm
new to PostgreSQL, aside from development mentioned on Mac OS X.
Compared with previous work in Oracle and MySQL, this rocks!

Thanks --

Paco Nathan
paco@famous.aspect.to

"a little Java + XML + SQL + X3D = conversational characters"