Lost ability to run PHP from cmd prompt & Dreamweaver

Help, I went to Dreamweaver to try out some php code & can't get any php to run, not even Hello World. Went to the CMD prompt typed PHP and got:

Microsoft Windows XP [Version 5.1.2600]

© Copyright 1985-2001 Microsoft Corp.
C:\Documents and Settings\Ron>php

Zend Optimizer requires Zend Engine API version 220051025.

The Zend Engine API version 220060519 which is installed, is newer.

Contact Zend Technologies at http://www.zend.com/ for a later version of Zend Op

timizer.

The only new software I installed since last time I used PHP w/Dreamweaver is the PHP runner update. Did I get a new Zend from you or did something update overnight without my knowledge?