When you access to most of the pages in Events Booking backend (for example Events Booking -> Categories or Events Booking -> Events), at the right, there is a menu called Tools which you might need to use in some special cases as explained below:

Tools -> Fix Database Schema

This tool is usually used when you update from old version of Events Booking to new version but the update process was failure for some reasons (or when you import Events Booking data from a different site - using an older version of Events Booking than the current site). Access to this menu item will help updating database schema to latest version and make sure Events Booking works properly on your site

Tools -> Purge URLs

Events Booking store all of it's URLs in database table called eb_events. These urls are cached URLs, mean urls might still point to old resources in some special case (for example, when you imported Events Booking data from a differnt site to this new site or you created an event with same title in the past, then delete it for some reason and re-create a new event with exactly same title/alias)

That's when you have to Purge URLs so that Events Booking will re-create new URLs and point it to new resource. Access to Tools -> Purge URLs usually help solving these issue