4.9 kernel panics and crashes

[Jeffrey Wheat]

I've got a server that has been rebuilt from the board up that is
crashing
every few hours with various page faults. This is a FreeBSD 4.9 system
with
a P4 3.2G HT processor, 2G of DDR, 3ware 6400 controller, 2 Intel
Fast100
ethernet cards on an Intel D865PERL motherboard. 

The server runs Exim 4.30 and clamav-devel out of a current ports cvs
update.
Here is one the current crashes:

May  6 08:15:14 mail /kernel:
May  6 08:15:14 mail /kernel:
May  6 08:15:14 mail /kernel: Fatal trap 12: page fault while in kernel
mode
May  6 08:15:14 mail /kernel: fault virtual address     = 0x8018
May  6 08:15:14 mail /kernel: fault code                = supervisor
read, page not present
May  6 08:15:14 mail /kernel: instruction pointer       = 0x8:0xc017aab8
May  6 08:15:14 mail /kernel: stack pointer             =
0x10:0xe911acc8
May  6 08:15:14 mail /kernel: frame pointer             =
0x10:0xe911acd4
May  6 08:15:14 mail /kernel: code segment              = base 0x0,
limit 0xfffff, type 0x1b
May  6 08:15:14 mail /kernel: = DPL 0, pres 1, def32 1, gran 1
May  6 08:15:14 mail /kernel: processor eflags  = interrupt enabled,
resume, IOPL = 0
May  6 08:15:14 mail /kernel: current process           = 7035 (tar)
May  6 08:15:14 mail /kernel: interrupt mask            = none
May  6 08:15:14 mail /kernel: trap number               = 12
May  6 08:15:14 mail /kernel: panic: page fault
May  6 08:15:14 mail /kernel:
May  6 08:15:14 mail /kernel: syncing disks... 128 14 1
May  6 08:15:14 mail /kernel: done
May  6 08:15:14 mail /kernel: Uptime: 8m40s
May  6 08:15:14 mail /kernel: twe0: failed to delete unit 0
May  6 08:15:14 mail /kernel: Automatic reboot in 15 seconds - press a
key on the console to abort

If anyone can offer advice, please email me. I am willing to try
anything at this point. A side note, acpi has not been built into this
kernel per warnings of instability.

Many thanks in advance,
Jeffrey