Fixed it!

Here's the answer for anyone else who does this.

I was trying out a tutorial, which was available at ibm.com, and obviously using an older version of the framework, they referred to Zend.php (which has been replaced by Zend Loader I believe).

In the file it had
'require once 'Zend.php'
which I correctly changed to
'require once 'Zend_Loader.php'

..but, i had overlooked the next line which tried to load the controller using Zend rather than the loader

ie Zend::loadClass('Zend_Controller_Action');

should have been Zend_Loader::loadClass('Zend_Controller_Action');

New to Zend, but many years of debugging in other areas, still frustrates the crap outta me!

Good luck all!