Sometimes ADE gets its registration/activation confused and in a semi-authorized state.
Unfortunately, it often then gives misleading error messages about what is wrong. (I don't think ADE2.0 went through any product test.)
The message you have seen is a common incorrect message.
Try completely removing any authorization using ctrl-shift-D to ADE (cmd-shift-D if on Mac).
Restart ADE, and then reauthorize with your Adobe ID.
