The problem with the website and the registration process should be directly forwarded to the webmaster because this is an error that needs to be fixed server-side.
Luckily, there is a way to contact the maintainer/developer/webmaster through the email. Access the page and click the linked URL: http://docmorph.nlm.nih.gov/docmorph/contact.htm
Note: If you have a default email client, it will launch automatically and the TO: field will have the email from the website.