I tried the Northanger Abbey book. There was a problem with the table of contents: the links took me to a page or so before the chapter. This happened in Calibre's ebook-viewer too. Apart from going to the wrong page, using the TOC links didn't cause the book to close or any other problem that I noticed.
I would try deleting the books and reloading them, and if that didn't help then you could try logging out of your account (from the Glo's Settings-->Account page) to rebulld the Glo's database, in case it has been corrupted somehow. Not sure what else to suggest, short of a full factory reset.