Try to configure selinux in permissive or disabled mode.
I had the same problem. I was trying to install moodle and failed. I got the same error above.
I configured selinux to permissive to see if this is the root cause and indeed I was able to install.
My problem was that I have opened moodle archive (moodle...tar.gz) as a regular user under his home directory and moved it to apache's DocumentRoot. This got the selinux content field to be wrong.
I have enable selinux and opened the tar.gz archive directly under DocumentRoot (/var/www/html). This gave the right content attribute to the files (httpd_sys_content_t). I was able to run moodle with selinux enabled.