Hi @maxtim,
I see two problems with the paths above.
/var/www/html/osTicket//osta/php/functions.php
has one too many forward // slashes.
And
/var/www/html/osTicket/upload/include/
includes the /upload directory, which shouldn’t be uploaded. The contents of the /upload directory should be uploaded, not the directory itself. 😉
In any event, I’m glad you managed to sort this out. Thanks for posting your solution.