Changing your email address needs to be done through SymAccount.

Log into Connect using your old SymAccount credentials.

1. Visit your profile page by clicking the "My Profile" option under the "Account" menu.
2. Click the "Edit Account" option on your profile page.
3. Directly under your username, click the "SymAccount" link in the sentence that begins with "To change your password ..."
4. You should be taken to your SymAccount edit page where you can change your email address, SymAccount password, and the contact details that are stored in the SymAccount system.
5. Once you've successfully changed your SymAccount information, your Connect account will be synchronized with the updated information from SymAccount.

There's a link on your user profile page and detailed instructions in the Connect FAQ:
http://www.symantec.com/connect/faq

if you still receive the error message, contact one of the admin.