Hi Edward,
go here and download the binary package, you may have to search for other dependencies on the same site?:
https://pkgs.org/ubuntu-15.10/ubuntu-universe-i386/screenlets-pack-all_0.1.6-0ubuntu1_all.deb.html
you could also try changing your software sources download location, I had mine set to "Main server" but had to change it to "USA" (don't hold your breath!), as @anon42388993 has pointed out above; you may have to wait as there are many packages missing from the repo's at the moment!: