Button Icons!?!

Button Icons!?!

I can't for the life of my figure this out!

I'm trying to make two buttons, one with a left arrow, and the other with a right arrow

My HTML:
<button id="left_theme"></button>
        <button id="right_theme"></button>

My Javascript:
$("#left_theme").button( {icons: {primary: "ui-icon-triangle-1-w"}, text: false } );
$("#right_theme").button( {icons: {primary: "ui-icon-triangle-1-e"}, text: false } );

My folders are set up like this:
project:
images:
-- website related images --
javascript:
jquery-1.4.1.js
jquery-ui-1.8.custom.min.js
-- a bunch of other javascript files --
stylesheets:
dot-luv
images
- the theme images --
jquery-ui-1.8.custom.css
project_stylesheet.css
index.html


And for whatever reason, those buttons are created without any icons!  

Does anyone have any clue what's going on? @_@