Did you read the XAMPP for Linux Page?http://www.apachefriends.org/en/xampp-linux.html
(down a bit)
startftp Starts the ProFTPD server. Via FTP you can upload files for your web server (user "nobody", password "lampp"). This command activates the ProFTPD permanently, e.g. if you restarts XAMPP in the future FTP will stay activated.
Looks like you might need the command - (as root, su, or sudo of course)
A - after this, when you start LAMPP - ProFTP should also start. I don't have version 1.7.7 running on my LAMPP box, so there might be an issue I am unaware of.
B. - ProFTP is keyed to the user 'nobody'. At one point they had sett the default password to 'lampp' - gee a security hole you say?? I think they may have fixed that, but not fixed the FAQ. BTW the configuration file is /opt/lampp/etc/proftpd.conf . I recall having to muck about a bit to get an encrypted password configured.
I just checked my box remotely, and the facts are basically correct.
There are more - BE CARFEUL - troubleshooting hints here - they are very specific and should not be used unless you have 'exactly that problem'http://www.apachefriends.org/en/faq-xam ... l#sicherer