There has yet to be any word from SchedulesDirect whether they will resume supporting WinXP with JSON.
Can I assume that the silence means "no"?
Once again, it's not that we're not supporting Windows XP, it's that you're using an application with outdated libraries that don't support Amazon's modern load balancer.
I've already told you that the XMLTV project's SD-JSON grabber works fine on Windows XP. That's proof that SD runs on Windows XP.