It looks like no one has responded to your post yet. Answering the following questions may help offer more information so others in the Apple Support Communities can help find a solution for you:
What are you trying to do (add your email address to the Mail app on your Mac so you can send and receive email, or are you trying to add your Apple ID so you can use services like FaceTime, iMessage, iTunes and the App Store)?
Do you need help recovering your login information?
What happens when you try to login (do you get an error message, or are you not sure how to do that)?