According to your post, you do not have Zend Optimizer installed. Zend Optimizer and Zend Scripting Language Engine are not the same thing. It appears as though your server has ionCube installed. ionCube is a similar product to Zend Optimizer and uses some of the same scripting and extensions. When you install ionCube, it also installs the Zend Scripting Language Engine and the Zend Extension Manager. After you install Zend Optimizer that field will have a new line below "Zend Technologies" that says:

with Zend Optimizer v3.3.3, Copyright (c) 1998-2007, by Zend Technologies

(Depending on your OS, the latest version is going to be v3.3.3 or v3.3.0a).