I replied to that one.
Your time is whacked out because you where setting the gmt to -24.00 hours.
If your server is located locally in your town it is the same timezone as you.
Now phpbb3 seems to adjust time from gmt or utf/utc they call it
Your time offset is 10 so your adding 10 hours onto the server time. Thus it is logical to me that your GMT offset if phpbb3 is using that like
vb or invisionboard and your server is indeed local to you then you would put -10 in the GMT as realistically your trying to cancel out the forum offset as server time should be right on for you.