I am trying to install WP Foro on a 100% fresh wordpress (first plugin) and I get in the backend

[Table 'wp_hamuw.zWFUo_wpforo_boards' doesn't exist]
SELECT * FROM zWFUo_wpforo_boards WHERE `status` = '1'

and then on the front page

Warning: Undefined array key 9 in /var/www/vhosts/xxxx/httpdocs/wp-includes/nav-menu-template.php on line 210

Warning: Undefined array key 9 in /var/www/vhosts/xxxx/httpdocs/wp-includes/nav-menu-template.php on line 210

Warning: Undefined array key 9 in /var/www/vhosts/xxxx/httpdocs/wp-includes/nav-menu-template.php on line 210

Warning: Undefined array key 9 in /var/www/vhosts/xxxx/httpdocs/wp-includes/nav-menu-template.php on line 210

Warning: Undefined array key 9 in /var/www/vhosts/xxxx/httpdocs/wp-includes/nav-menu-template.php on line 210

As it is a clean install, I wonder what the problem is 😉