[Admin]

In forumdisplay.php replace this:

      if ($foruminfo[allowicons] and $thread[pollid]!=0) {
        $thread[icon]='<img src="{imagesfolder}/poll.gif" alt="Poll" width="15" height="15" border="0">';
      }

with this:

      if ($foruminfo['allowicons'] and $thread['pollid'] != 0) {
        $thread[icon] = '<img src="{imagesfolder}/poll.gif" alt="Poll" width="15" height="15" border="0">';
      } elseif ($foruminfo['allowicons'] and $thread['sticky']) {
        $thread[icon] = '<img src="{imagesfolder}/sticky.gif" alt="Sticky" width="15" height="15" border="0">';
      }

Then create an image named sticky.gif in the images folder.