I install xampp on my debian 7,and when I try to start it, I have gotten an error message
start apache fail
/opt/lampp/lampp start
Starting XAMPP for Linux 1.8.2-2...
XAMPP: Starting Apache...fail.
XAMPP: Another web server is already running.
XAMPP: Starting MySQL...ok.
XAMPP: Starting ProFTPD...ok.
when debian7 start,it will start apache2. so you should stop it first,than try to start lampp.
/etc/init.d/apache2 stop
/opt/lampp/lampp restart
that maybe work.try it.