Error message

• Warning: Illegal string offset 'field' in DatabaseCondition->__clone() (line 1817 of /home/users/alicja/public_html/includes/database/query.inc).
• Warning: Illegal string offset 'field' in DatabaseCondition->__clone() (line 1817 of /home/users/alicja/public_html/includes/database/query.inc).
• Warning: Illegal string offset 'field' in DatabaseCondition->__clone() (line 1817 of /home/users/alicja/public_html/includes/database/query.inc).
• Warning: Illegal string offset 'field' in DatabaseCondition->__clone() (line 1817 of /home/users/alicja/public_html/includes/database/query.inc).