cheesegrits
Support Gopher
It may just be the forum permissions on this specific forum. Are all the posts you have this issue with in this 3.1 Alpha forum?
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.