ANS 1001 untold stories

Permission denied in Unknown on line 0

if you install apache/php and get the following error:
Warning: Unknown: failed to open stream: Permission denied in Unknown on line 0
Then consider to check the permissions.

What user/group has the apache?
ps -ef | grep apache

Who owns the files in your htdocs?

...

Because it is most likely that you need to chown your htdocs, and or add a user to the correct group.