Invalid login errors usually mean that either the username or password you are trying to log in with are incorrect. This can also happen if the password does not meet password requirements (at least 8 characters, both upper and lower case and at least 1 digit).
First, try to reset your password using the Forgotten your username or password? link on the WebJunction login page. If that fails or the password reset email does not arrive, contact OCLC Support with the email address that you requested your account with.