My Plone and zopectl daemon keep dying

I'm using Plone4 and zope and everytime i start ./instance fg, there is error like this.

So i changed command from fg to start and did again.(bin/instance start) But everytime i start zopectl start and plonectl start, the daemon process soon died and got message like "daemon manager running; daemon process not running ".

I tried those by root and normal user both. And checked whether other user use my 8080 port, but there was no user using my port.

So i think it is maybe the problem of html but I'm not sure that can be possible.
In my /etc/apache2 000-default.conf, the DocumentRoot is /var/www/html, which the html file of default apache page is in there(index.html). But no html file of my website is in there.
Could it be possible that plone and zope daemon process keep dying because there's no html about my site?
If it's not, why do the plone and zope are keep dying? I need to know about the cause and i have to fix it as soon as possible.

Error details are very important: Formerly, you got a "Permission denied" error; now, you get an "Address already in use" error. The error you get now means that your Zope/Plone server tries to bind to a port (i.e. a service access point) already used by some other process. Locate this process, terminate it and try again.

If you need further assistance, it may help when you post your "zope.conf" file: it will tell us whether or not you need to start your Zope/Plone as "root".

If running "buildout" produces errors, it might be a good idea to post its output. Maybe, you should even look for someone in your neighbourhood for help at your place.