I've run into a really weird issue. I was debugging a server 500 error script on our EC2 instance and found that we didn't have ioncube loaders installed. So I went to go install them and I created a new file at /etc/php.d/zend.ini and initially I inserted the value of extension=/usr/local/ioncube/ioncube_loader_lin_5.3.so and restarted httpd at which point it told me:

The ionCube Loader is a Zend-Engine extension and not a module
Please specify the Loader using 'zend_extension' in php.ini
PHP Fatal error:  Unable to start ionCube Loader module in Unknown on line 0

So I changed the contents of zend.ini to zend_extension=/usr/...etc. Now when I attempt to restart httpd I get this error:

Starting httpd: (98)Address already in use: make_sock: could not bind to address [::]:80
(98)Address already in use: make_sock: could not bind to address 0.0.0.0:80
no listening sockets available, shutting down
Unable to open logs

I can't even run /etc/init.d/httpd stop without it erroring. I've since removed zend.ini to see if that's what caused it and it doesn't seem to be.

Any ideas?