E_AUTH_BAD_DEVICE_KEY_OR_PKCS12

I used my Adobe Digital Editions really often and never had any problem.

Today, I tried downloading a book from the same site I always download it (public library) and it says: E_AUTH_BAD_DEVICE_KEY_OR_PKCS12

I've tried to unauthorized the mac, but ADE answer impossible to eliminate authorization.

I saw in in the forum the following instruction:

Macintosh:

    quit Adobe Digital Editions.

    Navigate to /Users//Library/Application Support/Adobe/Digital Editions and drag the activation.dat file to the trash

But I don't have Digital Editon in the application Support:

Can you help me? Many thanks!