Darnit. @schoolboy, would you generate me a log (I think the instructions on in post #265 or there-a-abouts) and check the console-log? I'll PM you an email address.
One thing to consider, too: Have you made any template-override changes into the tpl_checkout_one_default.php? The v1.0.10 -> 1.0.11 update introduced some required changes into the template_default version.