Is there something about the design of TorBrowser that blocks the ability to upload files to Web sites, or is there something wrong with my TorBrowser installation?
UPDATE: I figured out that TorBrowser won't access files that aren't on a local drive. When I copied the files I was trying to upload to the Desktop, everything went fine - but attempting to access
\\\SERVER\SHARE\file.ext fails silently. It also fails reading HTML files this way, which still leaves the question: Why?