The reason the YLD site says you need to use the same email address is that when you sign up for the different YLD email lists, they need to check that you are a member, and that's how they look you up to verify that. This is not the case for classes, though.

When you sign up for classes, it is not necessary to use the same email address you used to sign up for YLD. The person who enrolls people in classes uses the email address you used when you signed up for the class, which was your regular address.

If you don't want to use that address on the class list, just go to the web site for each class (the link should be in emails you received for the classes).

For each list, click Edit Membership (near upper left). The next page should walk you through how to change your email address. You may first have to do something to associate your Yahoo ID with your membership, but hopefully you can work that out by following the instructions.

Kitty