Hi Paul, because of time constraints, I just had time trying to find a solution of this problem.
There are two possibilities that causing jquery fails in execution:
1. If you add the javascript library directly in header.php, there is likely a reference jquery called twice.
2. Jquery Reference was called after the lightbox or wp-poll javascript , you can check it via view source.
because my limited skill of javascript management order on the header, then my solution are :
1. Add the jquery reference into header.php manually.
After <head>
i put <script type='text/javascript' src='/wp-includes/js/jquery/jquery.js?ver=1.7.1'></script>
2. Modifying/removing scripts that generate jquery reference.
open wp-polls.php
line 202 delete wp_print_scripts('jquery');
line 224
from wp_enqueue_script('wp-polls', plugins_url('wp-polls/polls-js.js'), array('jquery'), '2.50', true);
into wp_enqueue_script('wp-polls', plugins_url('wp-polls/polls-js.js'), array('jquery'), true);
line 243
wp_enqueue_script('wp-polls-admin', plugins_url('wp-polls/polls-admin-js.js'), array('jquery'), '2.50', true);
wp_enqueue_script('wp-polls-admin', plugins_url('wp-polls/polls-admin-js.js'), true);
its not perfect, but hopefully it helps