Hi,
From what I can see on your checkout, the problem is still the same. Your template is not displaying error messages. For example, if you don't validate the captcha, fill the rest of the form and register, the system will refuse the registration and it should normally tell you that the captcha validation code was missing, but on your website, it doesn't say anything.
Switch to the default template of Joomla and try again.
Do you get an error message in that case ?
What does it says ?
We didn't get any admin login in the first message of this thread, so I'm not sure what you mean.