jquery $(document).ready problem with working

jquery $(document).ready problem with working

Hey. i using $(document).ready(function() to start roundabout. its like this:

<script type="text/javascript">
$(document).ready(function()
{
      $('ul').roundabout({
      shape: 'figure8',
         duration: 1800,
   });
</script>

Problem is, sometimes (and its rare) roundabout dont load and list set im classical html style, vertical with no roundabout moving, clicking etc.

Reloading page make it workin again.

Where is the problem, or it is another good method to start roundabout or other script?