The console error that you noted above:
Code:
Console errors:
Uncaught ReferenceError: $ is not defined at index.php?main_page=checkout_payment:100Uncaught ReferenceError: $ is not defined at index.php?main_page=checkout_payment:188
implies to me that your template's /common/html_header.php isn't loading jQuery (or loading a woefully old version). Make sure, too, that your template includes /jscript/jscript_framework.php (that's the AJAX support interface).