Why do I get the "no access" graphic?

I have Complete protection set for a downloadable PDF file through the Membership plugin. However, no matter what I do, I get the "No Access" graphic. The link masking works fine. If I set the PDF file's Protected Content group to "none" it loads properly, but any other group fails to display the file.

I have created a positive rule in the access level named "Many Things" to allow the page to display and the "default" and "Book" groups to be downloaded. I have created a member and added the "Many Things" membership level to it. The page displays fine when logged in, and does not display when not logged in, so the positive rule is working. However, the PDF file does not display if I set it to the "default" or "Book" groups. Instead, I just get that No Access graphic.

What am I missing?