Community
Welcome to the Autodesk Community, Julie!
You are receiving that error because your AutoCAD LT 2013 license has been upgraded to an AutoCAD LT 2014. However, we can still activate this license for you because the 2014 has not yet been activated.
Please send me a private message (click on my name and then "send this user a private message") with your request code and I will generate the activation code for you.
Thank you!