If you see the following error when submitting a form:
Warning: date() [function.date]: It is not safe to rely on the system's timezone settings
This simply indicates that php has no default timezone set within your hosting account's php.ini file.
You need to add (or have your host add) your timezone information to php.ini:
date.timezone = timezone name
date.timezone = America/Louisville
A list of timezones can be found at: http://php.net/manual/en/timezones.php