Can`t delete files from Adobe Digital Editions 4.5

In my Adobe Digital Editions library there are several fikes/icons of th same ebook. Instead of the name of the book, Adobe Digital Editions shows the file- names. When I delete those files from my library, they re-appear after the next start of Adobe Digital Editions . I also removed und re-installled Adobe Digital Editions including all filrd without any success.

How can I purge and fix my library?