Efront installálásnál ezt a hibaüzenetet kaptam Fatal error: Call to undefined function mb_substr () in /var/www/html/efront/libraries/includes/check_status. Php on line 126 Tudja vki h mit jelent? Mi a megoldás? (tovább lent)

$settings['post_max_size'] = array('value' => $ini_settings['post_max_size']['local_value'],

'recommended' => $ini_settings['upload_max_filesize']['local_value'],

'status' => mb_substr($ini_settings['post_max_size']['local_value'], 0, -1) >= mb_substr($ini_settings['upload_max_filesize']['local_value'], 0, -1) ? 1 : 0,

'name' => 'post_max_size',

'help' => 'Post_max_size should be set at least equal to upload_max_filesize');

ennek a része