[General] Secuirty pin and forget pass

[Destroy666]

1. One issue per thread, please. If your initial question has been answered, mark it as solved and open a new thread for the unrelated question.
2. The error is straightforward - you have to upload that file. If you don't know where to get it (it's a part of a plugin, this one I believe: http://mods.mybb.com/view/at-home-polls), you can upload an empty PHP file with that name instead.