Hi, I'm trying to install Zend Optimizer on my server and I had the following error. I got help from there forums, but not enough.

Seems that package php is not suitable for your system.
Please, replace a package php(ZendOptimizer/zui_files/php with you php binary, that you have on your system or compile it (no metter what version)

Where would I find my php binary?

you will only have a php binary when you've compiled the cgi version of php on your server

ok, how do I go about doing this?

you build binary php same way as apache module. Just skip appx option in configure options.