When I try and subscribe, the form tells me it has had a "Processing Error"
There is a bug that some iPad users are running across when signing up which causes an error in the card processing. Your card is not charged, and there is nothing wrong.
We are working on resolving the bug, but in the meantime you can use your laptop to sign up. The site and videos are optimized for iPad use, so you can still use the iPad to access the site.