I get this with my library (emedia) all the time. Its easy to fix, and after fixing it you can use diffrent/multiple formats.
I downloaded an eBook and transferred it to my Sony Reader. I was able to read it before, but now when I try to open it, Sony Reader shows a 'Protected Page' error message. What should I do?
This is a known issue with some Sony Readers, wherein if borrowed eBooks in one format are used on the Reader, then a borrowed eBook in an alternate format is transferred to the same Sony Reader, eBooks in the most recently transferred format will function while eBooks in the first format will show the 'Protected Page' error. To use the desired format, transfer a title in that format again. All borrowed titles in this most recently transferred format will be usable.