New computer - new instance of ADE already activated - unable to download Ebooks - getting all kinds of error messages

Had ADE on previous office computer at work (I am a librarian at an academic library, and we use Adobe Digital Editions to read EBSCO Ebooks offline).  Got a new computer [PC, Windows 7 64-bit OS] several months ago.  Just installed new version of ADE on this computer, but when I try to download Ebooks I get "Error! Check Activation" When I try to delete my Computer Authorization, I get another error message (Unable to erase authorization. Please try after some time). And if I try to remove one of the borrowed Ebooks that should have expired on their own, I get "Activation Server Error code: E_ADEPT_INTERNAL".  Please help me, so I can help our students for future reference.  Thank you