Apache upgrade 2.2 to 2.4

Apache is running a threaded MPM, but your PHP Module is not compiled to be threadsafe.  You need to recompile PHP.

In your httpd.conf find the line that loads the event MPM:

LoadModule mpm_event_module modules/mod_mpm_event.so

Replace it with one that loads the prefork MPM:

LoadModule mpm_prefork_module modules/mod_mpm_prefork.so

Of course you still need to load the PHP5 module (libphp5.so) and the corresponding config file somewhere.