I haven't had any problems getting library books through Overdrive. I have gotten both epub and pdf formats. Have you tried downloading a book from Overdrive? Once it is downloaded I "add it to my library" in ADE (Adobe Digital Editions). It shows up and transfers easily to the Libre. Its a great way to get new/besteller ebooks, so I hope it works for you!
An advantage of the Libre is that it does not have an internal clock, so once the library book expires in ADE (after 14 or 21 days depending on your library) just don't sync your Libre to ADE until you are done with the book. If ADE sees it has expired, it will delete it from your Libre. Learned that the hard way.
