Install Cubase AI 4 - Activation

Hello,

I bought a Yamaha synthesizer and I’ve got with it Cubase AI 4 CD with it.
I Installed the software and I’m trying to activate the software.
I created steinberg account, chose the program that I want to activate and entered the code
that was on the CD (there are 7 characters on it) and I only get a message that says the code is Invalid.

The syncrosoft control center tells me that I’ve a permission to use the software until 11/11/13.

so what can I do? I have only this CD and only this 7 characters…

Thanks