"too many clients" and no cure

Hi,

I experience some trouble with my PG server. I get the error message
"too
many clients". Ok, so I checked the manual and adjusted the
max_connections and shared_buffers, but still the server denies access,
if
there are about 100 connections. I just recently increased the shared
buffers from 10000 to 50000 and the system shared memory fom 128m to
about
800m. Still the error occurs at 100 active connections.

Here's some system info:
OS is SuSE Linux 9.1 (kernel 2.6.7-040722)
I have 1GB of RAM.
PG is 7.4.2
Parameters in postgresql.conf:
max_connections = 500
shared_buffers = 50000
sort_mem = 2048

sysctl -a | grep shm
kernel.shmmni = 134217728
kernel.shmall = 805306368
kernel.shmmax = 805306368

ipcs -ls
------ Semaphore Limits --------
max number of arrays = 128
max semaphores per array = 250
max semaphores system wide = 32000
max ops per semop call = 100
semaphore max value = 32767

Thanks,
Tom