For those who've been having problems with the unban link not showing up, I've found the problem.
In /mod/user.php Find:
PHP Code:
$users=$DB_site->query("SELECT userid,username FROM user WHERE username LIKE '%".addslashes(htmlspecialchars($findname))."%' ORDER BY username");
Replace that with:
PHP Code:
$users=$DB_site->query("SELECT userid,username,usergroupid FROM user WHERE username LIKE '%".addslashes(htmlspecialchars($findname))."%' ORDER BY username");
The reason the unban link wasn't showing up was simply because the 'usergroupid' column wasn't selected from the database. Therefore when it tried to search for the usergroupid of the banned user (in this case '8') it couldn't find anything because the 'usergroupid' column wasn't selected to look in.