Hello

Can you please reupload the file includes/admin.inc.php?

I re-uploaded it and still get the error. Every link in the admin area works except Forum Settings. I went from 2.4.18 to 2.4.19 I skipped 2.4.18.1

Ok, it was an attempt.

Also regular users are getting 500 errors sometimes clicking on bookmarks and sometimes selecting category.

You are sure, that this error did not occure before you updated your forum?

Tschö, Auge

PS: I got an empty page (but no HTTP-status 500), when I opened the posting form to write this answer.