Sorry to ask thiis, jeanpaul, but WHY do you want to use a command, for a start - script that doesn't exist?
You could as well ask, WHY you are not able to use the command "/etc/init.d/apache2_initd start" and the answer would be as well, that this start - script doesn't exist and so the command is not executable.
You can list all start - scripts on your system with the command: ls /etc/init.d/