Sure enough, I have the same exact problem. Permissions set to both 777 and 775 - I even removed the "test" part of the install.php to see what would happen, and although I can get past it then, it still can't write to include/ .
Fedora Core 3
php-4.3.11-2.4
httpd-2.0.52-3.1
owner/group is apache/apache which is what the server runs as.
If anyone finds an actual answer, I'd love to hear it. I am running plenty of other PHP-MySql-based things with no issues.
-- UPDATE
ok, so it was selinux that was causing the issue. I haven't learned how to tweak it to work properly, but you can disable it on the httpd daemon.
First run sestatus, you should see this line:
httpd_disable_trans disabled
then edit:
/etc/selinux/targeted/booleans
and change the line: httpd_disable_trans=0 to httpd_disable_trans=1
run sestatus again you should see
httpd_disable_trans active
Ok- you're almost there. Now restart apache
/sbin/servicec httpd restart
now go to the install.php page and you should be golden. If I figure out how to run selinux with httpd properly I'll let everyone know. Also, there was a link above that led to a good post that led me to the selinux config issue and said to disable with the GNOME gui that Fedora includes. Since like many of you I don't run a GUI on the server and only have console abilities (I know I could export X and use the GUI tools, but hey) I wanted to detail what to edit. If you have access to the GUI, you can just adjust the policy with that and it will do the same exact thing I assume.