Ok, here's what happens: I can't download from the original link (which seems to have been changed now btw, to a html page instead) with 'wget'. Going through the anonym.to anonymizer doesn't work either, and in any case whenever a link fails to work for me I always also try through a torproxy to remove any issues with my local firewall.

However, it works if I go to the web page, and then to the download section and downloads from there. I think the site is doing some magic to allow downloads when you visit the mother page first, but disallows a direct link.

My proxy logs:
Request: www.ticalc.org/pub/win/vtiskins/dummyskin89.zip
which is the download via the web page. Now I use the same link, but with curl (just the headers in this case):
>curl -I http://www.ticalc.org/pub/win/vtiskins/dummyskin89.zip
HTTP/1.0 403 Forbidden

Anyway, I got it downloaded now.