Error message

• Warning: date_timezone_set() expects parameter 1 to be DateTime, bool given in format_date() (line 2133 of /usr/local/share/drupal-7.102/includes/common.inc).
• Warning: date_format() expects parameter 1 to be DateTimeInterface, bool given in format_date() (line 2143 of /usr/local/share/drupal-7.102/includes/common.inc).