An statement causes postmaster to die

Sean Kelly (lists(at)shortestpath(dot)org) reports a bug with a severity of 1
The lower the number the more severe it is.

Short Description
An statement causes postmaster to die

Long Description
I am having a problem trying to run an update on my database. The SQL that causes the problem is listed below, as is some data from the tables used.

The message I see is one of the following. It's either:

Server process (pid 22322) exited with status 11 at Sun Apr 22 16:14:15 2001
Terminating any active server processes...
Server processes were terminated at Sun Apr 22 16:14:15 2001
Reinitializing shared memory and semaphores
DEBUG: Data Base System is starting up at Sun Apr 22 16:14:15 2001
DEBUG: Data Base System was interrupted being in production at Sun Apr 22 16:14:06 2001
DEBUG: Data Base System is in production state at Sun Apr 22 16:14:15 2001

or

Server process (pid 22408) exited with status 11 at Sun Apr 22 16:18:05 2001
Terminating any active server processes...
NOTICE: Message from PostgreSQL backend:
The Postmaster has informed me that some other backend died abnormally and possibly corrupted shared memory.
I have rolled back the current transaction and am going to terminate your database system connection and exit.
Please reconnect to the database system and repeat your query.
NOTICE: Message from PostgreSQL backend:
The Postmaster has informed me that some other backend died abnormally and possibly corrupted shared memory.
I have rolled back the current transaction and am going to terminate your database system connection and exit.
Please reconnect to the database system and repeat your query.
Server processes were terminated at Sun Apr 22 16:18:05 2001
Reinitializing shared memory and semaphores
DEBUG: Data Base System is starting up at Sun Apr 22 16:18:05 2001
DEBUG: Data Base System was interrupted being in production at Sun Apr 22 16:14:15 2001
DEBUG: Data Base System is in production state at Sun Apr 22 16:18:05 2001

I am running PostgreSQL 7.0.2 on Linux 2.2.16 using an Intel Celeron 333 and 128Mb RAM.

Sample Code
isp=> \d domain_tbl
Table "domain_tbl"
Attribute | Type | Modifier
-----------+-------------+----------
domain | varchar(80) | not null
ident | varchar(5) | not null
max_email | integer | not null
username | varchar(10) | not null
added | timestamp |
Indices: domain_tbl_ident_key,
domain_tbl_pkey

isp=> SELECT * from domain_tbl where domain='test.domain';
domain | ident | max_email | username | added
-------------+-------+-----------+----------+------------------------
test.domain | test | 10 | sean | 2001-04-22 16:17:22+01
(1 row)

isp=> update domain_tbl set max_email='15' where domain='test.domain';
pqReadData() -- backend closed the channel unexpectedly.
This probably means the backend terminated abnormally
before or while processing the request.
The connection to the server was lost. Attempting reset: Failed.
!>

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