Hey hey !!! The Zend server did not load correctly. The cause is the apache selinux policy. To fix that:
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cd /usr/local/ZendStudioServer-4.0.0 <= change to what ever dir you installed in
chcon -R system_u:object_r:httpd_modules_t lib/
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Now restart apache and it should work.
google it by "ZendExtensionManager.so: failed to map segment from shared object: Permission denied"