I used your search but no similar problems so..
I have added all the files and made all the code changes.
I then deleted all cache except .htaccess
I go to phpbb_seo/phpbb_seo_install.php
All steps are ok, but it directs me to log into adm panel I get
Fatal error: Call to undefined function get_formatted_filesize() in /home/bebobox/public_html/forum/includes/acp/acp_main.php on line 337
In acp_main.php is
// Get forum statistics
$total_posts = $config['num_posts'];
$total_topics = $config['num_topics'];
$total_users = $config['num_users'];
$total_files = $config['num_files'];
$start_date = $user->format_date($config['board_startdate']);
$boarddays = (time() - $config['board_startdate']) / 86400;
$posts_per_day = sprintf('%.2f', $total_posts / $boarddays);
$topics_per_day = sprintf('%.2f', $total_topics / ...