No it’s not possible for me to update the installation on the server, because it is the server of the university of applied sciences. Maybe my professor can do something to update it. He already contacted you per email.
The operating system of the server is an Ubuntu 16.04.3.
If I’m using the absolute paths on the server like /home/knime/… then everything works as expected. Only if try accessing the files via knime protocol, I get the error messages.