The Post recently redesigned their games area, and I believe this coincided with the .jpz/.puz versions of the puzzle ceasing to be available. I was downloading it from a couple of other sites as well as using an app on my mobile phone - all of them stopped working at the same time.
It's unfortunate that the Post/CrosSynergy has limited our options for solving the puzzle. If it's about generating ad revenue, why not create a subscription service like the NYT has done so successfully? I would gladly pay - I will not solve using a clunky Java applet.