8.2.3 PANIC with "corrupted item pointer"

Hello all,

I'm using PG 8.2.3:

PostgreSQL 8.2.3 on i686-pc-linux-gnu, compiled by GCC gcc (GCC) 3.3.6

I happened to notice this error in the log when my application was refused
a db connection (quite unexpectedly):

PANIC: corrupted item pointer: offset = 3308, size = 28
LOG: autovacuum process (PID 18165) was terminated by signal 6
LOG: terminating any other active server processes
LOG: all server processes terminated; reinitializing
LOG: database system was interrupted at 2007-06-21 12:27:13 SAST
LOG: checkpoint record is at D6/F00F418C
LOG: redo record is at D6/F00C24B8; undo record is at 0/0; shutdown FALSE
LOG: next transaction ID: 0/2090506603; next OID: 101300203
LOG: next MultiXactId: 35676; next MultiXactOffset: 85365
LOG: database system was not properly shut down; automatic recovery in
progress
LOG: redo starts at D6/F00C24B8
FATAL: the database system is starting up
LOG: record with zero length at D6/F138DDA4
LOG: redo done at D6/F138DD7C
LOG: database system is ready

Just prior to the panic, an INSERT was executed three times and rejected
as expected because of a unique constraint index.

Database size is about 180GB and growing.

Any comments would be appreciated.

Regards
Henry