Incorrect df -k output

[Newtunes Support]

Hi all!

I have the folliwing issue on 6.1 and 6.2
df -k utility always shows me incorrect disk usage.

Server with 6.1 on board:
===========================
xxxxx# uname -a
FreeBSD xxxxx 6.1-RELEASE-p6 FreeBSD 6.1-RELEASE-p6 #0: Mon Sep 18 17:06:13
MSD 2006     root at xxxxx:/usr/obj/usr/src/sys/GENERIC  i386

xxxxx# df -k
Filesystem  1K-blocks     Used    Avail Capacity  Mounted on
/dev/ad4s1a  76866422 51507978 19209132    73%    /
devfs               1        1        0   100%    /dev
*/dev/ad6s1d  77879478 75006042 -3356922   105%
/usr/home/ftp/pub/ARCHIEVE*


xxxxx# du -sk /usr/home/ftp/pub/ARCHIEVE
75006042        /usr/home/ftp/pub/ARCHIEVE

And I have such bug oh 6.2 on second server too.
================================================

xxxxx# uname -a
FreeBSD xxxxx 6.2-RELEASE FreeBSD 6.2-RELEASE #0: Fri Jan 12 11:05:30 UTC
2007     root at dessler.cse.buffalo.edu:/usr/obj/usr/src/sys/SMP   i386

xxxxx# df -h
Filesystem     Size    Used   Avail Capacity  Mounted on
/dev/ad0s1a    496M     36M    420M     8%    /
devfs          1.0K    1.0K      0B   100%    /dev
/dev/ad0s1d    1.9G    425M    1.4G     23%    /tmp
/dev/ad0s1f    136G     70G     55G    56%    /usr
*/dev/ad0s1e    3.9G    3.6G    -21M   101%    /var*
/dev/ad2s1d    144G     25G    108G    19%    /hd2
procfs         4.0K    4.0K      0B   100%    /proc

xxxxx# du -sh /var
202M    /var
========================

What can be a reason of this malfunction? I tryed to bounce serve4rs but it
had not fix the issue.
Please advise.

Thanks
Dmitry