Please check the following:
1. Admin Panel -> Settings -> scroll down to Date & Time.
2. open up your php.ini and look for the "date.timezone = " directive. Make sure that it is set to the correct timezone.
list of support timezones available here:
http://nz.php.net/manual/en/timezones.php(http://nz.php.net/manual/en/timezones.php)
3. Also check the actual time on your server.
Good luck!
(now where did that caffeine go?)