> Is there any file in the local directory

<path>/www.domain.tld/ contains all of the HTML files and 
images from the site, but none of the ZIPs. Also, when I 
open www.domain.tld/download/archive_01.zip in a Web 
browser, I can download it successfully.

> Any errors in hts-log.txt ?
Nope, only the "Warning moved treated" warnings. Weird.