LAMPP does not work quite like standard LAMP stacks.
please try starting LAMPP with this command (as root)
See if LAMPP starts ok, please...
Was LAMPP stopped when you issued that command??? or were you trying to 'start Apache'????
LAMPP is run by a bash script (/opt/lampp/lampp), with a set of delimited options (arguments) that are invoked by that script. What I am saying is you may not be able to use some Apache CLI options.
The arguments are outlined in the LAMPP FAQ's -http://www.apachefriends.org/en/xampp-linux.html
(down toward the bottom)
You can also open the bash script (/opt/lampp/lampp) with an editor - look around line 128 for the arguments available (cases)