Thanks to this post on the WordPress support forums, I just got the “Press This” button working again.  This seems to be a problem with WordPress installs with HostGator as the host.  I wanted to post it here in case anyone else is running into the same problem of trying to use the “Press This” button and it returns a ‘404’ page.

Edit the text in the “Press This” link

Replace:

u=’+e(l.href)+’

With:

u=’+e(l.href.replace(/\//g,’\\/’))+’

via WordPress › Support » “Press This” results in 404.