PHP/Zend optiomizer fails to load

Hello,

I installed Zend optimizer sometime back, but never bothered to check
whether it's working or not. I was looking for something else in my
httpd error log, when I came across this . Could anybody shed light on
the problem?

Failed loading /usr/local/Zend/lib/ZendOptimizer.so:
/usr/local/Zend/lib/ZendOp
timizer.so: undefined symbol: zend_get_ini_entry

To get info on my system configuration please click on
http://www.esaravana.com/phpstuff.php

Cheers!
Sundar