> here's the page containing the link to the pdf (PDF
> red button)
> <http://ricette.giallozafferano.it/Zucchine-a-scapece>
> .html
and the link location is:
<http://www.giallozafferano.it/images/PDF/GZRic-Zucchine-a-scapece.pdf>

Those are two different sites and httrack does not by default span sites.
Had you used the near option (get non-html related) or allowed related sites
(+*.giallozafferano.it/*) or allowed all pdfs (+*.pdf) you would have gotten
them.