Crazy md5,sha256,bzip2 behaviour, frequent crashes RAM problem?

Hi,
i've struggling to build sysutils/coreutils and a crazy thing happens:
each time i do 
fetch ftp://ftp.gnu.org/gnu/coreutils/coreutils-6.9.tar.bz2
and while ls -l gives the exact same size (5384378), md5,sha256 give different checksums each time!
I do this same fetch from another machine _at_ work and it gives the correct size, checksums.
I scp the wierd coreutils-6.9.tar.bz2 from the wierd FreeBSD box to a linux, and i get the the
same wierd checksums, so i conclude the problem happens at fetch time.
Wierd problems on FreeBSD most commonly have bad memory as the root cause.
Do you have any other idea of what it might causing it??
Also i have frequent crashes at high loads with this machine.
It runs 7.0-RC2 FreeBSD 7.0-RC2

Here is the kgdb session from the most recent crash:


doroot_at_smadev:/usr/obj/usr/src/sys/ACHIX7# kgdb kernel.debug /var/crash/vmcore.5
kgdb: kvm_nlist(_stopped_cpus):
kgdb: kvm_nlist(_stoppcbs):
[GDB will not be able to debug user-mode threads: /usr/lib/libthread_db.so: Undefined symbol "ps_pglobal_lookup"]
GNU gdb 6.1.1 [FreeBSD]
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i386-marcel-freebsd".

Unread portion of the kernel message buffer:


Fatal trap 12: page fault while in kernel mode
fault virtual address   = 0x2000028
fault code              = supervisor read, page not present
instruction pointer     = 0x20:0xc07bb175
stack pointer           = 0x28:0xe6383794
frame pointer           = 0x28:0xe63837bc
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, def32 1, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = 49307 (bsdtar)
trap number             = 12
panic: page fault
Uptime: 14h22m21s
Physical memory: 979 MB
Dumping 183 MB: 168 152 136 120 104 88 72 56 40 24 8

#0  doadump () at pcpu.h:195
195             __asm __volatile("movl %%fs:0,%0" : "=r" (td));
(kgdb) backtrace
#0  doadump () at pcpu.h:195
#1  0xc07504e3 in boot (howto=260) at /usr/src/sys/kern/kern_shutdown.c:409
#2  0xc07506df in panic (fmt=Variable "fmt" is not available.
) at /usr/src/sys/kern/kern_shutdown.c:563
#3  0xc0a40e7c in trap_fatal (frame=0xe6383754, eva=33554472) at /usr/src/sys/i386/i386/trap.c:899
#4  0xc0a410e0 in trap_pfault (frame=0xe6383754, usermode=0, eva=33554472) at /usr/src/sys/i386/i386/trap.c:812
#5  0xc0a41a39 in trap (frame=0xe6383754) at /usr/src/sys/i386/i386/trap.c:490
#6  0xc0a2b33b in calltrap () at /usr/src/sys/i386/i386/exception.s:139
#7  0xc07bb175 in vfs_hash_get (mp=0xc416f7d4, hash=5561646, flags=Variable "flags" is not available.
) at /usr/src/sys/kern/vfs_hash.c:72
#8  0xc0945029 in ffs_vget (mp=0xc416f7d4, ino=5561646, flags=2, vpp=0xe6383918) at /usr/src/sys/ufs/ffs/ffs_vfsops.c:1320
#9  0xc0927625 in ffs_valloc (pvp=0xc80bc330, mode=33188, cred=0xc5910700, vpp=0xe6383918) at /usr/src/sys/ufs/ffs/ffs_alloc.c:957
#10 0xc0956885 in ufs_makeinode (mode=33188, dvp=0xc80bc330, vpp=0xe6383b94, cnp=0xe6383ba8) at /usr/src/sys/ufs/ufs/ufs_vnops.c:2238
#11 0xc0956ff0 in ufs_create (ap=0xe6383a8c) at /usr/src/sys/ufs/ufs/ufs_vnops.c:194
#12 0xc0a568b2 in VOP_CREATE_APV (vop=0xc0b8ac60, a=0xe6383a8c) at vnode_if.c:206
#13 0xc07d38ff in vn_open_cred (ndp=0xe6383b80, flagp=0xe6383c78, cmode=Variable "cmode" is not available.
) at vnode_if.h:112
#14 0xc07d3cc3 in vn_open (ndp=0xe6383b80, flagp=0xe6383c78, cmode=420, fp=0xc4d80288) at /usr/src/sys/kern/vfs_vnops.c:94
#15 0xc07d1957 in kern_open (td=0xc5fa2a50, path=0x28250100 <Address 0x28250100 out of bounds>, pathseg=UIO_USERSPACE, flags=2562,
    mode=420) at /usr/src/sys/kern/vfs_syscalls.c:1028
#16 0xc07d1ec0 in open (td=0xc5fa2a50, uap=0xe6383cfc) at /usr/src/sys/kern/vfs_syscalls.c:995
#17 0xc0a41435 in syscall (frame=0xe6383d38) at /usr/src/sys/i386/i386/trap.c:1035
#18 0xc0a2b3a0 in Xint0x80_syscall () at /usr/src/sys/i386/i386/exception.s:196
#19 0x00000033 in ?? ()
Previous frame inner to this frame (corrupt stack?)
(kgdb)                                                             

-- 
Achilleas Mantzios

KOSOVO IS SERBIA FOR EVER