That tutorial you followed is a bit dangerous. It seems it tells you to replace the default X11 with a new one, which is a really bad unnecessary idea.
Where did you change your local variable? If you used .profile or .bash_profile it is only valid for your user. To affect all users you need to change /etc/paths. But I don't think it has anything to do with the PATH var.
Regarding your question, this means Apache is not loading the correct PHP module. (libphp5.so)
Check the creation date of /usr/libexec/apache2/libphp5.so
If it predates your build time, then it was not replaced.
First turn off Apache (either in Settings or by running sudo apachectl stop in the console).
Then rename /usr/libexec/apache2/libphp5.so -->sudo mv /usr/libexec/apache2/libphp5.so /usr/libexec/apache2/libphp5.so.bak
Then go to the source dir and run make install. (if you have deleted the directory, the makefile or ran make clean you will need to start the compilation process again)
Then check if libphp5.so exists at /usr/libexec/apache2/. If it does not exist, then your compilation parameters are wrong. If it does, go to step 5.
Rename the new /usr/libexec/apache2/libphp5.so to libphp5.4.8.so (or the version you're installing).
Backup httpd.conf --> sudo cp /usr/libexec/apache2/httpd.conf /usr/libexec/apache2/httpd.conf.bak
Edit httpd.conf --> sudo nano /usr/libexec/apache2/httpd.conf and change LoadModule php5_module libexec/apache2/libphp5.so to LoadModule php5_module libexec/apache2/libphp5.4.8.so
Put the old libphp5.so back. --> sudo mv /usr/libexec/apache2/libphp5.so.bak /usr/libexec/apache2/libphp5.so
Restart apache (in settings or with sudo apachectl start)
Let me know if it worked for you
Depending on your needs, you could try XAMPP: http://www.apachefriends.org/en/xampp-macosx.html. I find it a lot easier to configure and run than OS X's Apache/PHP combo.
– Vidar Ramdal – 2012-10-11T13:56:58.423