This will sure work

When attempting to download an Adobe eBook a second time, I received the error 'Error getting license/License server communication problem: E_LIC_ALREADY_FULFILLED_BY_ANOTHER_USER'. What should I do?

In order to download a single Adobe eBook on multiple computers, Adobe Digital Editions must be activated using the same Adobe ID on each computer.

To activate Adobe Digital Editions using an Adobe ID…

1. Open Adobe Digital Editions.
2. Select Library > Authorize Computer….
   The 'Authorize Computer' dialog box is displayed.
3. In the appropriate fields, enter the email address and password for your Adobe ID.
4. Click 'Activate'.
   Your computer is activated to your Adobe ID.
5. Click 'Finish' to close the 'Setup Assistant' dialog box.
   Adobe Digital Editions is activated using an Adobe ID. Repeat this process on each computer on which you intend to download Adobe eBooks.