Hello Ray,
It will be hard to recreate this on the live server as I do not want to prevent anyone from completing a sale. Locally, I did get an error message at the top of the shopping cart on the checkout page, right below the NEXT button.
Warning: chdir(): No such file or directory (errno 2) in C:\wamp64\www\newreptilesncritters\webassist\framework\ajax_wrapper.php on line 22
Does this help narrow it down?