Just purchased a 770, and I'm pretty sure I love it, that's of course if I learn how to use it!

I downloaded an e-book to my laptop, then transferred the files to my 770. When I click on the files, the PDF reader opens, but then I get a message 'document encrypted, enter user password then a pop up says, password needed. I've typed the password from the ebook.com site where it was downloaded from, and a few others - but they are all incorrect.

Please, can someone help me?

Cheers, Cathryn