If you have problem that public library PDF and ePUB cannot coexist on my reader. you can’t open library ebook on sony reader PSR-600, it show error message “Protected Page”.
Some library books are Adobe PDFs, some are Adobe EPUB (both DRM protected). You can have one or the other – not both types of DRM – on the Reader.
From the Sony website (this was for the 505, but I’m sure it is the same for the 300 and 600).
This issue happens when Adobe DRM protected ePub and PDF eBooks which have been borrowed, both exist on the Reader.
You can borrow epub and pdf books from your library, but be careful to never have both epub and pdf library books on your reader at the same time, as there is a conflict and you will not be able to access them. A Protected Page! error occurs on the Reader when opening a borrowed book that is in the ePub or PDF format when borrowed Adobe DRM-protected ePub and PDF eBooks exist on the Reader at the same time.
To solve this issue, please follow these steps:
1. Delete all borrowed books from the Reader and transfer them again from Adobe Digital Editions or eBook Library.
2. Verify that all borrowed books are of the same format(ePub or PDF) before transferring them to the Reader.