Seems to be a dead link.. the .etd file is an XML file which points <bookfileurl> to a long url on lightningsource.com, which is DOA. No PDF at all at any of these sites.
So.. can you just attach the .pdf file here for review instead?
This is one problem that I'm seeing with many of these e-book sites... they partner with 1, 2, 3 other sites, and when one or two of them goes down, your whole experience is ruined, and you just end up going elsewhere, most-likely to a competitor.
If you can't fix EVERY link and EVERY resource, you should remove them or do something about them so users aren't burdoned with this kind of detective work. It gets exhausting.
Why not just host the .pdf yourself, on your own network, so you don't rely on someone else breaking THEIR pages/links/machines?