I have sent emails to Yahoo
I have sent emails to the hosting provider to have this rectified but their reply emails state that this is not possible, please see below:
Thank you for writing to Yahoo! Customer Support.
We're sorry, the feature, Zend Optimizer, you are mentioning is not currently available through Yahoo! Web Hosting and we do not have an estimated date as to when or if it will be available. However, we'll pass your comments on to our Development team for further consideration.
We are always looking for ways to make Yahoo! Web Hosting more useful to our users, and we will be sure to keep your question in mind as we continue to make improvements to our service.