ADE Ebook Can't be added into Library

Hi,

I recently purchased an ebook from university bookstore. I downloaded the file and got an ACSM file. I tried adding this file into the ADE, but it showed: E_LIC_ALREADY_FULFILLED_BY_ANOTHER_USER

I recall using this ebook under the same account on a different computer, but I don't think that should affect my access since the other computer has already been reset.

Thanks,

Steven