I think I have this figured out.

Although my host said that ZEND was installed, I don't believe it was.

Here's the ZEND from bizhat's demo site:

This program makes use of the Zend Scripting Language Engine:
Zend Engine v2.2.0, Copyright (c) 1998-2007 Zend Technologies
with the ionCube PHP Loader v3.1.32, Copyright (c) 2002-2007, by ionCube Ltd., and
with Zend Extension Manager v1.2.0, Copyright (c) 2003-2007, by Zend Technologies
with Zend Optimizer v3.3.0, Copyright (c) 1998-2007, by Zend Technologies
And here's the ZEND from MY site:

This program makes use of the Zend Scripting Language Engine:
Zend Engine v2.2.0, Copyright (c) 1998-2007 Zend Technologies
Obviously missing the ZEND! Grrrrrrrr!