When you upload your avatars this is not displayed.

Warning: require(./../includes/class_loader.php): failed to open stream: No such file or directory in

Fatal error: require(): Failed opening required './../includes/class_loader.php'

Solution:
open root/download/file.php

find
require($phpbb_root_path . 'includes/class_loader.' . $phpEx);

replace with
require($phpbb_root_path . 'phpbb/class_loader.' . $phpEx);
find
$phpbb_class_loader = new phpbb_class_loader('phpbb_', "{$phpbb_root_path}includes/", $phpEx);
replace with
$phpbb_class_loader = new phpbb_class_loader('phpbb_', "{$phpbb_root_path}phpbb/", $phpEx);