The error indicates that you are using the wrong Adobe ID. You can use the ebook only with the original Adobe ID on which you downloaded it. It doesn't matter whether you have ADE 1.7.1 or 1.7.2. Also it doesn't matter which computer as long as it has ADE registered to the same Adobe ID.
If you had ADE on the original computer not tied to an Adobe ID but anonymous, I think I have read on Adobe's website that you can authorize it on an Adobe ID and then your downloaded books will be converted to that ID. Otherwise you can try to re-download the book with the correct Adobe ID.
Last edited by pietvo; 03-03-2010 at 04:32 AM.
Reason: spelling errors