As jnealand stated, xSchedule is no longer supported on Mac. Old versions are still working for some peoples setups, but I think it is understandable to expect that overtime there will probably be more and more broken.
It seems like your biggest issue is getting updated sequences to your Windows machine that CAN run xSchedule successfully. I've seen many people use Google Drive, OneDrive, etc to keep sequences in sync across machines. I'd imagine you could sequence on your Mac and utilize one of those tools to also be running on your Windows machine. It would at least make it easy to get the files back and forth, even if it might mean you have to tell xSchedule there were some updates and needs to refresh.