I got a lot of problem with Adobe

For absolutely no reason, when I try to read a book on my kobo ereader, sometimes it tells me I cannot open the books I just borrowed at the library, it says I dont have the authorization to open it. It is completely random, with some books it works and with others it doesn't. I've tried just about everything and when my ereader has decided it doesnt want me reading that or that book, I simply have to chose another one, It will never work! It seems to me like adobe really doesn't give a shit about it's free programs and that I just have to live with a shitty program. Does someone have a better explanation?

Thx!