It sounds as if your Athens cookie is installed ok because you are getting into Dawsonera and finding the book you want.
I haven't encountered this before, but I wonder if the problem is the pre-installed pdf reader? I would try downloading Adobe Reader and see whether this works.
When you select the download option, on the screen which pops up, there is a link which says "Get Adobe Reader".
If you are still having problems, please give me a call on 0121-476 1181 ext 1526 and I will try to help!