The jquery that comes built in with wordpress doesn't fully work.
I have a theme that calls jquery using wp_enqueue_script() so that there are no conflicts if any other plugins need jquery.
However, my theme will not work with WordPress's built in jQuery. Instead, i have to replace the wordpress jQuery with the content from the latest jQuery over at jQuery.com and then my theme will work and all other plugins and features that rely on jQuery continue to work.
Please email at email@example.com if you have any questions about the bug. Thanks!