mmyron wrote:You mean I have to add an existing users credentials to proftpd.conf?
No, you simply have to enter an login an existing UNIX User from /etc/password.
For example. you can login to FTP with your personal UserID and your personal password, if you do so, FTP will start in your home directory. As there is no User for Xampp, you may create a new User (with the "adduser" command) for Xampp (for example call it "xampp") and provide /opt/lampp/ or /opt/lampp/htdocs as home directory.
If you do so, you also should change ownership of /opt/lampp/htdocs to User "xampp" and finally edit httpd.conf and apply "User = xampp", after then Apache will be started from User xampp. Otherwise you might get problems that the FTP User xampp does not have the same rights as the Apache process, which also reads and creates files. This is in fact basic Linux knowledge and not Xampp knowledge.