pgbench could not send data to client: Broken pipe

Howdy,

I'm running pgbench with a fairly large # of clients and getting this error in my PG log file.

Here's the command:
./pgbench -c 1100 testdb -l

I get:
LOG: could not send data to client: Broken pipe

(I had to modify the pgbench.c file to make it go that high, i changed:
MAXCLIENTS = 2048

I thought maybe i was running out of resources so i checked my ulimits:

ulimit -a
core file size (blocks, -c) 0
data seg size (kbytes, -d) unlimited
scheduling priority (-e) 0
file size (blocks, -f) unlimited
pending signals (-i) unlimited
max locked memory (kbytes, -l) unlimited
max memory size (kbytes, -m) unlimited
open files (-n) 2048
pipe size (512 bytes, -p) 8
POSIX message queues (bytes, -q) unlimited
real-time priority (-r) 0
stack size (kbytes, -s) unlimited
cpu time (seconds, -t) unlimited
max user processes (-u) unlimited
virtual memory (kbytes, -v) unlimited
file locks (-x) unlimited

This is Pg 8.3.10. Redhat 64bit, the system has 48 cores, 256G of ram..

Any idea what would be causing the error?

thanks

Dave