Can you give me the link to those instructions please - I don't recognise this at all?
Getting WebDAV onto the server was as simple as adding the feature, but it had to be configured.
https://docs.moodle.org/33/en/WebDAV_repository
Seeing as how it did not work and is continuing to be a problem, I think reinstalling Moodle may be the best option...
Seems a coworker of mine was able to resolve the issue.
They managed to get past the error by going to a page that did not have a calendar settings directly and turned blocks editing to 'on' and it resolved the issue.