jQuery error - $ is not defined : <p>The following code:</p>

<pre><code>$('body').mousemove(function() {
    clearTimeout(hide)
    var hide = setTimeout(function() {
        hidePlayer()
    }, 2000)
    showPlayer()
})
</code></pre>

<p>works fine if I link to a remote jquery library:</p>

<pre><code>&lt;script src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"&gt;&lt;/script&gt;
</code></pre>

<p>or if I link to my local file twice:</p>

<pre><code>&lt;script src="assets/js/jquery.min.js"&gt;&lt;/script&gt;
&lt;script src="assets/js/jquery.min.js"&gt;&lt;/script&gt;
</code></pre>

<p>but using only one jquery script tag:</p>

<pre><code>&lt;script src="assets/js/jquery.min.js"&gt;&lt;/script&gt;
</code></pre>

<p>gives me the following error:</p>

<pre><code>Uncaught ReferenceError: $ is not defined
</code></pre>

<p>I've tried different versions of jquery, using window.onload, replacing $ with jQuery, tried type="text/javascript" and charset="UTF-8"... I'm stumped.  Any help is appreciated.  </p>
