Hello,
Look, every theme version requires an appropriate version of XStore core plugin, check the changelog https://xstore.8theme.com/update-history/ It means if you use XStore 6.1.5 then XStore Core plugin should be 1.4.5, if you use XStore 6.1.4 then XStore Core plugin – 1.4.4 according to changelog.
In your case you installed XStore 6.1.4 and core plugin 1.4.5, that’s why you had a problem. There was no need to reinstall WordPress.
I have updated theme, now both theme and plugin are up to date and you can proceed with demo content import if you decided to reinstall all.
Regards