The <div>s and the <p> within the <li> are block elements. You should place display:inline on those <div>s and <p>.
Also, any HTML in the $description variable that are block-level elements are going to cause the same behavior.
EDIT: You have much bigger problems on your site that are causing the issue.
You are repeating your <div id="movienav"></div> code over and over again, each with a <ul> and one <li> item in it. Firstly, you cannot have more than on container with the same, unique ID on it. Second, those <div>s are block elements, thus why they are not displaying inline.
You need to set up your structure to look more like this:
<div id="movienav">
<ul>
<li></li>
<li></li>
<li></li>
<li></li>
</ul>
</div>
Not the way you have it, then your style should work fine.