Hmm, how strange. This precise file (posted here) has been passed through my Mac; that is to say, I got the email through Mail.app, saved it to disk, uploaded it to my iDisk and linked to it. And now, evidently it's not working. However, the file in the email does work fine on Windows machines when I check my email directly through webmail. I know because I read the contents an hour or so ago on a friend's computer with Windows XP. wtf is going on here?