Code:
mysql_query("UPDATE users SET username = '" . filter($_POST['username']) . "', mail = '" . filter($_POST['email']) . "', motto = '" . filter($_POST['motto']) . "', rank = '" . filter($_POST['rank']) . "', credits = '" . filter($_POST['credits']) . "', activity_points = '" . filter($_POST['pixels']) . "', vip = '" . filter($_POST['vip']) . "' WHERE username = '" . filter($_POST['username_current']) . "'") or die(mysql_error());
Replace that query at line 59 with this. Should work thought didnt test it.