Regarding importing '.epub' files into your Adobe Digital Editions library, this works for me:
- note the location of the '.epub' file
- launch Adobe Digital Editions
- click on icon that shows list of books in the library (upper left-hand corner)
- find dropdown box 'LIBRARY' upper left
- click dropdown box arrow
- click on 'Add item to list' or 'Add item to library'
- dialog box opens; go to location of desired '.epub' file
- double-click on filename of desired '.epub' file
- last action shows filename in list of books in Adobe Digital Editions library
- find it in list, click arrow button to left, select 'open item'
- text of the epub book appears
Let me know if it works for you.