For running J!5.1 you must https://fabrikar.com/forums/index.php?wiki/update-from-github/ or include the new file manually https://fabrikar.com/forums/index.php?threads/joomla-5-1-and-fabrik-cannot-find-files-error.54473/post-285151 See also Announcements
Please see our announcement here.
hi rob, did you perhaps forget to update github. Just updated latest and we back to square one with all events missing.ah that was my bad, should be fixed in github and I updated your site with the changed file
-Rob