Hi there Denyce. Thanks for the note; apologies to hear you’re having issues. My guess is you had that item added to the header menu in 1.6.5, and what we’re seeing there is a carryover from that? In the 1.6.5 release events were just a category under the regular posts section; in 2.0 they’re a custom post type entirely. As a result you should be able to fix that by just going to Appearance –> Menus and changing the header link to events from /category/events to just /events, and it’ll carry over fine.
Let me know if that doesn’t work for you and I can keep troubleshooting. Cheers!