When I scroll through a book it remains on the page I opened

When I scroll through a book it remains on the page I opened and the only thing that changes is the page number but when I go out of the book and come back in it shows the new page but again when I scroll it remains on the same page and the only thing that changes is the page number..I have the latest version of Adobe Digital Edition 4.0.3.1103333 and also Adobe Reader is Version 11.0.10...Any idea's as to why this is happening?