Some players are still having trouble with the e-book, specifically stating the "navigation to webpage was cancelled". Again this has nothing to do with the software, entirely to do with the Internet explorer settings on your computer. It is specifically Internet explorer regardless of what browser you use. it mostly occurs with Windows XP.
Google "navigation to the webpage was cancelled windows xp" and there is ample information. Unfortunately I can't help it is more than this as it is a Windows issue to do with your computer's security settings.
in an unrelated problem, but also to do with the e-book software, some ebooks are still being automatically locked. make sure you have downloaded the latest version of the e-book software, as it helps the program on track what the problem is.