I have checked the provided URL but there is no web site configured for this domain name.
Anyway I assume that you have enabled 'capcha' image verification for your forum but for some reason it is not displayed on the registration page. I am afraid I cannot say what is causing this. You can try disabling the image authentication from the admin area for the forum. Check the registration and if it is working enable it again. If this does not resolve the issue you might consider using a different template.