Hello Robert,
Thanks very much for the interest in upgrading.
Yes -- Neil Jensen did make Hauptwerk v5+ compatible versions of his sample sets. It does appear that his website ( http://www.keymediaproductions.com/ ) doesn't currently support HTTPS, so if your browser won't allow access to the site because of that then it's probably simplest to email him directly:
neil_jensen [at] keymediaproductions.com
(I think you'd probably need to email him anyway to get download links for the v5+ versions of his sample sets anyway.)
Don't throw your Hauptwerk v3 (HASP) USB dongle away! You'll need that when upgrading to Hauptwerk v6 (v5+) so as to transfer your existing sample set licences off of it, and into the iLok system. You probably just need to install the driver in order to get your v3 dongle recognised by the computer for that.
I'm not sure whether/where MDA still hosts the downloads for the file HASP dongle (Hauptwerk v2-v4 Hauptwerk USB Key) driver publicly, but if you email Francois at support [at] hauptwerk.com I expect he'll be able to provide the necessary details.