memory management

Hi folks,
"FATAL 1:  palloc failure: memory exhausted" is the error and I have already
checked the FAQ and increased my memory allocation to 64M using limit/ulimit
as recommended.

moe: {2187} % limit
coredumpsize    unlimited
cputime         unlimited
datasize        131072 kbytes    (actually a little bit of overkill)
filesize        unlimited
maxproc         64
memorylocked    20916 kbytes
memoryuse       62744 kbytes
openfiles       128
stacksize       8192 kbytes

BSDI reports 64M of RAM available...
Nov 24 17:04:45 moe kernel: BSDI BSD/OS 3.0 Kernel #0: Mon Sep 21 23:32:40
FJT 1998
Nov 24 17:04:45 moe kernel: cpu = Pentium Pro model 3, stepping 4
Nov 24 17:04:45 moe kernel: real mem = 67108864 (64.00 MB)
Nov 24 17:04:45 moe kernel: avail mem = 64069632 (61.10 MB)

Systat|Swap reports 262M of virt memory
Disk 1K-blocks     Used  /0%  /10% /20% /30
sd0b    262140    73536  XXXXXXXXXXXXXX

Top looks like this
load averages:  2.53,  1.63,  1.18
10:38:49
58 processes:  4 running, 54 sleeping
CPU states: 25.8% user,  0.0% nice,  7.1% system,  0.0% interrupt, 67.0%
idle
Memory: Real: 48M/50M Virt: 71M/373M Free: 268K
  PID USERNAME PRI NICE  SIZE   RES STATE   TIME   WCPU    CPU COMMAND
19787 postgres      73    0   52M       39M run     0:14 31.70% 28.37%
postmaster

I am running PostgreSQL 6.4 as -su -c
/usr/local/pgsql/bin/postmaster -i -o -eF

When I tried /usr/local/pgsql/bin/postmaster -i -o -eF -d 6 -B 448
Top gave:
Memory: Real: 45M/50M Virt: 78M/374M Free: 332K

I thought I was making progress but It doesn't really look like it.

So here are the questions...
1) Why is the system running out of memory when there is plenty of virtual
memory available?
2) Is the -B flag going to solve this problem if I can get B high enough?
3) Does anyone have a reference of how to increase shared memory on BSD3.0?
(I know I shouldn't ask here but, gee whiz, I've searched everywhere
including the BSD manual and SysAdmin)

Enough whining,
TIA, JOHN