Zend Optimizer error : Failed loading /usr/local/Zend/lib/ZendExtensionManager.so

After Zend Optimizer installation you get the following error:

Failed loading /usr/local/Zend/lib/ZendExtensionManager.so:
/usr/local/Zend/lib/ZendExtensionManager.so: failed to map segment from shared object: Permission denied

this is because of ..the SElinux being ON.

to fix it follow the instructions:

1) Disable SELinux by editing /etc/selinux/config and setting SELINUX=disabled‘ there.
2) If you want SELinux enabled, you can remove SELinux protection from httpd by using system-config-securitylevel tool
3) If you want SELinux protection on httpd, use this to enable loading Zend modules: chcon -t httpd_modules_t `find /usr/local/Zend/lib -name \*.so`

Source here