I visit arXiv maybe five times a year, and every time I do the same "where the hell is the link" search. The problem is that the box with downloads appears to be part of the page chrome, not part of this particular entry.
Weird thing is that Firefox isn't doing anything when I click on that, either at from the site or from here. I had to fire up WGet, which showed me that the request gets bounced to a cached copy located at a different URL:
Like the place to view the problems, for me at least: PDF http://arxiv.org/pdf/1110.1556v1