On one of my Gentoo systems, the system date was off by 5 hours and some minutes. Adjusting the system date was only valid during that one boot up session. After the system was rebooted, the system date was off by 5+ hours again. Here is the fix:

# date MMDDHHMM
# hwclock -w
# rm /etc/adjtime
# hwclock -w

The command hwclock -w returned an error message "select() to /dev/rtc to wait for clock tick timed out". This would be the reason that the system refused the system date changes.

To fix that, edit /etc/conf.d/clock, and set:

CLOCK="local"
CLOCK_OPTS="--directisa" 

Then restart the clock service:

# /etc/init.d/clock restart

Check the system date now and see that your system is on the new time.