Sometimes if you activate a new plugin (or add code to your theme) or even if your theme/a plugin is updated the rewrite rules – which WordPress uses to handle requests – can be modified.
Every now and again such a change will not play nicely with existing rules and cause a situation like this one. Generally it shouldn’t happen but if and when it does, this is often a quick way of fixing things 🙂
Glad it’s sorted in any case and I will now go ahead and close this thread – but of course if we can help with anything else definitely feel free to create new topics as needed. Also, if you happen to have a moment to spare, we’d love to hear about your experiences with The Events Calendar so far over on our plugin review page.
Thanks again!