book opens but i cant turn pages....?

Hi i'm a new user of e-books , and it could start better. Im trying to read the "getting started" book and a sample book "sherlock holmes" but i cant get it to turn pages... when i click the next page the indicator line at the bottom moves and says it's on next page but the previous page just stays up. IF i shift the view to full scren or the other way around teh new page shows up . Extremely annoying... Anyone got an idea of what this is about?

/G