ошибка часового пояса после установки скрипта

я получаю сообщение об ошибке ----------

Warning: date(): It is not safe to rely on the system's timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected the timezone 'UTC' for now, but please set date.timezone to select your timezone. in /home/user/public_html/cdemo/_include/lib/lib.php on line 73

Warning: date(): It is not safe to rely on the system's timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected the timezone 'UTC' for now, but please set date.timezone to select your timezone. in /home/user/public_html/cdemo/_include/lib/lib.php on line 74



Error: E_WARNING
URL: http://mywebsite.com/demo/
File: /home/user/public_html/cdemo/_include/lib/db_common.php
Line: 69
Message: date(): It is not safe to rely on the system's timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected the timezone 'UTC' for now, but please set date.timezone to select your timezone.

Call stack:

File: /home/user/public_html/cdemo/_include/lib/db_common.php (Line: 69)
Function: date

File: /home/user/public_html/cdemo/_include/core/start.php (Line: 199)
Class: DB_Common
Function: connect

File: /home/user/public_html/cdemo/_include/core/main_start.php (Line: 12)
Function: include

File: /home/user/public_html/cdemo/index.php (Line: 15)
Function: include

как решить эту проблему ??