a error about PostgreSQL7.3.4's Log setting

Hi everyone,
My name is Ken working in Tokyo,Japan. Please forgive my
poor English.

We have been using PostgreSQL7.3.4 on a Map GIS engine
since last year.To tune the system, I need to get the log
from PostgreSQL7.3.4 and analyze it.

Here comes the problem. When a long SQL is excuted. I got
the error as follow

error:SQL Execute error 0 = Too much data was received.

when I removed the log setting from my postgresql.conf
file the sql was excuted without any problem and ended
normally. I appand my postgresql.conf and start shell as
follow.

postgresql.conf
----------------------------------------------------------------
#
# Message display
#
server_min_messages = log
# Values, in order of decreasing detail:
# debug5, debug4, debug3, debug2, debug1,
# info, notice, warning, error, log, fatal,
# panic
client_min_messages = log
# Values, in order of decreasing detail:
# debug5, debug4, debug3, debug2, debug1,
# log, info, notice, warning, error
silent_mode = false

log_connections = false
log_pid = true
log_statement = true
log_duration = true
log_timestamp = true

#
# Syslog
#
syslog = 1 # range 0-2
syslog_facility = 'LOCAL0'
syslog_ident = 'postgres'

LC_MESSAGES = 'C'
LC_MONETARY = 'C'
LC_NUMERIC = 'C'
LC_TIME = 'C'
----------------------------------------------------------------

start_pgsql.sh
----------------------------------------------------------------
pg_ctl start -D /data/pgsql -o "-i" -l
/data/pgsql/postgresql.log
----------------------------------------------------------------
develop environment
OS: solaris2.9
Apserver: Sun application Server 7
JDBC Driver: pg74.215.jdbc3.jar

can any friend help me, thanks a lot