Error messages during installation

During the installation process I get the following error messages though the respective programs are installed on the server:

iptables: command not found 
httpd: command not found 
useradd: command not found 
apachectl: command not found

This means that the programs mentioned are not in the path of your Linux installation. Please type

echo $PATH

on your command line, and make symbolic links to the programs in one of the directories that is in the path. For example, you can create a symbolic link to the program /path/to/apachectl in the directory /usr/bin by going into the directory /usr/bin and typing the following:

ln -s /path/to/apachectl apachectl

This creates a symbolic link named apachectl in the directory /usr/bin pointing to /path/to/apachectl.