After making some upgrades, including for php, I started getting these warnings in the apache logs
PHP Warning: Module 'apc' already loaded in Unknown on line 0
Warning: Module 'apc' already loaded in Unknown on line 0
PHP 5.2.13 (cli) (built: Jun 2 2010 16:24:43)
Copyright (c) 1997-2010 The PHP Group
Zend Engine v2.2.0, Copyright (c) 1998-2010 Zend Technologies
with the ionCube PHP Loader v3.3.10, Copyright (c) 2002-2009, by ionCube Ltd.
Turns out the upgrade added a php.d directory containing a apc.ini that also loaded the apc module.
So commenting out the extension loading in php.ini made the warning go away.
I also had to manually recompile some php module (specifically the ffmpeg one) and other were automatically updated by yum (but not until I added the REMI repository
Obviously google didn’t help at all and I just had to manually dig for the issue and it was by sheer chance that I noticed the new php.d directory. so hopefully this post will change that for others 
Thanks to your post, Google did help now
So, thanks!
Thanks man, Google sent you to help me..:) Thanks to both you & google..
So what the installation thinks ask me to add a module on php.ini while he do it by his self. By the way thanks
Thx man for having corrected Google
Now it helps! Cheers from Senegal.
Thanks man !
I got a debian squeeze and in my configuration i had duplicate files instead of symlinks in /etc/php5/mods-available and /etc/php5/conf.d
Your experience sharing helped me look at the right place
Thanks and fyi google is still up and running
Thks man
was helpfull!!