It was an error during the SQL command!
MySQL error number: #1064
MySQL error: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '%20src%20+%20'', '3.147.61.142')' at line 1
The SQL command:
INSERT INTO error_page_log (url, ip) VALUES ('http://bacsbokod.hu/js/highslide0/'%20+%20src%20+%20'', '3.147.61.142')

Backtrace:

File Line Class Type Function
/var/www/bacsbokod/data/www/bacsbokod.hu/classes/db.class.php 111 db -> db_error
/var/www/bacsbokod/data/www/bacsbokod.hu/config/config.php 130 db -> query
/var/www/bacsbokod/data/www/bacsbokod.hu/index.php 70 require