warning: timezone_open(): Unknown or bad timezone (Europe/Moscow) in /public_html/sites/all/modules/date/date_api.module on line 878.
warning: date_create() expects parameter 2 to be DateTimeZone, boolean given in /public_html/sites/all/modules/date/date_api.module on line 878.
warning: date_offset_get() expects parameter 1 to be DateTime, boolean given in /public_html/sites/all/modules/date/date_timezone/date_timezone.install on line 49.

В чём может быть проблема?