You have a conflict with JQuery and another script that's being loaded on the page. You need to do one of two things:
Remove the additional scripts one by one until you find the offending one
Change jQuery from using the dollar sign to a non-conflicting variable:
http://api.jquery.com/jquery.noconflict/
<script>
//Tell it something else is using the dollar sign
$.noConflict();
//Now instead of using the dollar sign, you use "jQuery"
jQuery( document ).ready(function( $ ) {
// Code that uses jQuery's $ can follow here.
});