i'm going to talkyou through this. together, we can do it.
RIGHT: in this thread there are to big grey reply buttons. one is on THIS POST and simply says "Reply". The other is right at the bottom of the thread, not attached to a post, and says "Reply to this thread". If you click either of those to GREY buttons, you will reply to the original post/the thread. as an example, take a look at this thread posted by martbowski:
codpieceface has clicked one of the GREY BUTTONS to reply to the thread. if i were to click the small "Reply" that is attached to codpieceface's post, right next to '^This' and which is not a grey button but just plain text, that would come out as a reply to codpieceface's post.