Postgres-7.0 dying

Got a bit of a problem here?!
I just upgraded to Postgres-7.0
I am getting the error shown below consistantly, not always in
the same place in the database build script.
When I installed 7.0 I did not migrate my data. Instead I chose
to rebuild all databases (6) and all tables (> 40) from scratch
from the raw data. This is a data warehouse so I just did a fresh
extract from the donor machine. Let me say a word about the method
I use to populate the tables in the databases. I extract the data
from the donor as tab delimited fields suitable for the psql 'copy'
command. I then 'copy' the data into the table and build indexes.
This technique has worked for almost a year now with older versions
of Postgres. The same exact data actually.

Hardware:
pII 550
lvd scsi drives (no file system is > 60% full)
Software:
FreeBSD 3.4 (Postgres 6.5.3 has been running on this system
for months without failure)
Postgres install:
cd /usr/local/pgsql/src
gmake
gmake install
============================================================
The important part of the postmaster startup script
---------------------------------------
[ -x /usr/local/pgsql/bin/postmaster ] &&
{
#
# BEWARE
# The command exec'd by the su statement below uses
# the default shell for user pgsql which is tcsh NOT sh.
# That explains the syntax for the output redirect.
#
su -l pgsql -c 'exec /usr/local/pgsql/bin/postmaster \
-i \
-B 128 \
-o "-S 1024" \
-D /usr/local/pgsql/data \
>& /var/postgresql/postgresql-7.0/startup.log'
echo -n ' pgsql'
}
==========================================================
The shell script which caused the error
---------------------------------------
#!/bin/sh

psql sis << \__EOD__
my_password
drop table stddmg;
__EOD__
rslt=$?

exit $rslt
==========================================================
The output of the above shell script
----------------------------------------
Password:
ERROR: out of free buffers: time to abort !

ERROR: out of free buffers: time to abort !

FATAL 2: elog: error during error recovery, giving up!
pqReadData() -- backend closed the channel unexpectedly.
This probably means the backend terminated abnormally
before or while processing the request.
connection to server was lost
ERROR: drop table stddmg failed
========================================================
At the time I got this error the script had successfully
create 6 databases and about 40 tables;

Any clues for the clueless?????

Thanks

hal