Well the first piece of bad news is that I can not try this theme out on my development system because it makes calls to other plugins that I do not have and they make no checks for the existence of those plugins which would be the right thing to do.
The next bad news is that there are badly written calls to javascript routines all over the place and very few of them where they actually should be. Having seen ClassiPress themes before I can only assume this is an old one or a very heavily customised one.
So – any edits I suggest here may still not be totally correct as it is really hard to analyse. But let’s at least try.
There are 4 separate header php files. I do not know which one is actually used or if all of them are but as they all essentially have the same calls in them. There is a block of directly loaded script statements that includes these 4:
<script type="text/javascript" src="<?php bloginfo('template_url'); ?>/jquery-ui-1.8.16.custom.min.js"></script>
<script type="text/javascript" src="<?php bloginfo('template_url'); ?>/jquery.ui.core.js"></script>
<script type="text/javascript" src="<?php bloginfo('template_url'); ?>/jquery.ui.datepicker.js"></script>
<script type="text/javascript" src="<?php bloginfo('template_url'); ?>/jquery.ui.widget.js"></script>
These appear to be the ones that are causing the current problems. Please note that word ‘appear’! I can not 100% confirm this. Now my suggestion for correcting this is not ideal but it should be safe and I see it is a method that the header php file uses already so I assume it should work. These 4 lines need replacing with:
<?php
wp_enqueue_script('jquery-ui-core');
wp_enqueue_script('jquery-ui-widget');
wp_enqueue_script('jquery-ui-datepicker');
?>
However, the custom.min,.js file that is currently being loaded does contain some other libraries so we may need to add to this but we wont know what with until these lines are replaced. As I say – this is not the ideal way to do it but it is the best I can do without pulling the theme apart and re-writing most of it!