Forum not Refreshing Itself

[Synnah]

YaBB SE Version: 1.5.5
PHP Version: 4.3.4
MySQL Version: 4.0.x
Server Platform: Unix, Linux, or BSD
Link to Forum: http://forum.swcity.net

Problem Description:
My forum has been having this problem where when you visit the board and someone has posted something new, you have to hit refresh for every page to see the NEW tags beside messages that have new posts in them.  You also need to hit refresh when you come to the main page to see what boards have new posts.

It's like the forum isn't refreshing itself to users.

What's wrong?