outlook time stamp on e-mails is an hour off since dst

when we send emails the time stamp on when we receive them is an hour
behind when there sent.

we have the "adjust for dst" off on the "day time properties " on the
time zone tab.
if we set it on, the time stamp appears to correct itself, BUT after a
period of time the "system time " jumps forward an hour. (by itself -
after as short as 1 hour or up to 4 hours)

I've tried to install KB931836, and I get " newer version of patch all
ready install" so the DST patch is not the issue.

any ideas..

system info :
MS XP sp2
MS outlook 2000


TIA