Yii中的Zend Data Cache配置

I am trying to enable Zend Data Cache in my Yii 1.1.12 but not able to do it. I downloaded Zend Server and from the installation folders, I managed to find the ZendDataCache.dll. I configured it in PHP as extensions after placing it in "ext" directory but still getting the error in Yii. When I do PHPInfo, I can see Zend references but not able to confirm if Data Cache is loaded or not. Screen shot of PHP Info and Yii errors are attached. What am I missing?