Redemption codes contain both letters and numbers. The other numeric codes on your insert, card, or email, such as the UPC code, are not your redemption code.
Make sure that you typed the code correctly. It is easy to confuse some numbers and letters, such as zero and one with the letters "0" and "I".
For more details you can also refer to http://helpx.adobe.com/x-productkb/global/redemption-code-help.html