When I click the link in my account activation email, I get an error message that the link has expired.

The link within your account activation email will expire after 7 days. If the link has expired, you will have to complete the Create Account process again. Go to the Create Account page to do so. Please have your member number available (found on the back of your membership card), and select a different username than the original one you had used.

Once you create the account, the activation email may take up to 10 minutes to appear in your inbox.