max_connections beyond 47 causes hang

Hi,

The largest number I can set max_connections to in postgres.conf is 47, regardless of how large I set the shared_buffers.  I have tried setting this value to as large as 512 but it does not help. 

I have installed postgres 7.2 from the ports collection of FreeBSD 4.7.  I use the shell script 010.pgsql.sh to stop and start the server (this script just calls pg_ctl in a fancy way).

Do I need to restart the server differently or am I missing out on something?  I read the section on Managing Kernel Resources in the admin docs but nothing is said about FreeBSD.  But I don't think it has to do with that because I can set the shared buffer value high enough.

Please help,

Babak.