Yeah, that was all it was.
So if you have any application that uses zend optimizer and you're running php 5.2. If you upgrade to php 5.3 it will stop working. You'll need your application reencoded for php 5.3.
If you want to install zend guard which is the replacement for optimizer for php 5.3
Just download 'Zend Guard Loader (Runtime for PHP 5.3)' 32bit or 64bit from...
Put 'ZendGuardLoader.so' where every you want it to load from.
Edit php.ini to load the extension
restart php5-fpm, all set.