You will need to install reading software.
1. Try reading the book in mobi format.
Get a mobipocket reader free here:
MobiPocket Reader from
http://www.mobipocket.com.
or
2. Try reading the book in lrf format.
You can get Sony's free ebook library software, with a free lrf reader here:
http://ebookstore.sony.com/downloadclient.html
I hope this helps.