Trouble Getting my Sidebar Widget-aware

I am trying to get my theme widget-aware. I put in the code from the automattic website, but I’m still getting this when I go to manage my widgets:

“You are seeing this message because the theme you are currently using isn’t widget-aware, meaning that it has no sidebars that you are able to change. For information on making your theme widget-aware, please follow these instructions.”

Here is my sidebar code:

<div id="sidebar">
<ul id="sidebar">
<?php if ( !function_exists('dynamic_sidebar')
        || !dynamic_sidebar() ) : ?>
<li id="about">
  <h2>About</h2>
  This is just me testing to see if ANYTHING shows up in the sidebar!

 </li>
<?php endif; ?>
</ul>
</div>

The about section is showing up.