Looking for help on removing screw

Hello, I am trying to remove an old bracket for my attic ladder. However, having a hard removing this particular screw(is it even a screw?) shown on the left. It has a button head on the other end. Can you please help? Attachment 37236 (http://www.doityourself.com/forum/attachments/hardware-fasteners/37236-looking-help-removing-screw-unnamed.jpg)