It isn´t possible to open all of the bought books on Adobe Digital Edition although it is possible to open them on the Cybook Odyssey E-Book reader?

i have bought some books on my Cybook Odyssey. There i can read them. I have also tried to save them on my Computer with Windows 8. under using the Adobe digital Editions. With most of the books it works well but two of them Show only blank sides, whild the demo Versions do work.

thanks for help!