a) you are running Red Hat Linux, but this the Windows Forum
b) you already have an Apache installed on your Red Hat Linux and is already running.
If you want to run Xampp instead, you should at least stop that Red Hat Apache, and/or de-install it. Dont ask me, how to do so, that is a Red Hat question, not a Xampp question. Or, de-install Xampp and forget about it, because you already have an Apache running on your PC.
P.S.: Why do you spam this Xampp Forum with your question? There is no need to ask 4 times the same question in 4 different subforums. This is against the netiquette.