No More Processes

I'm trying to run PostgreSQL 7.4.1 on Mac OS 10.2.6. I'm running into
problems when the number of process for the postgres user reaches 100.
When that happens I get a "No More Processes" message in the terminal
shell. From then on, that user is "locked". I can't even ssh into it.

I've tried to increase the max process limit in my startup script, but
I'm still getting the same behavior. Here's part of my script:

#!/bin/sh
. /etc/rc.common

StartService ()
{
ulimit -u unlimited # before -u = 100
var=`ulimit -a`
ConsoleMessage "$var" # shows -u = 532 (which is good I think)
su - postgres -c '/usr/local/bin/pg_ctl -o "-i" -D
/Library/PostgreSQL/data -l /Library/PostgreSQL/data/logfile.log start'
}

Please. Any help would be greatly appreciated. Thanks!