What is this error: E_STREAM_ERROR:

I am unable to download a book from e-library to Digital Editons 2 so I can transfer it to my Nook.  I get the following error:  E_STREAM_ERROR:   Error getting license, license server communication problem.  The library can't help me, Adobe won't.  This happened with the last 2 books, but one month ago it was working fine.  Help, please