[Zope] error on creating Tutorial instance

[SDA]

Ah well, the "issues" keep on coming.

I've got "The Book of Zope" from Beehive, and I'm running Zope 2.6.x
from Debian "Sarge" distribution.

Following the suggestions in the help menu, from within Zope, on how to
install the Zope Tutorial, I'm presented with this error:

"Zope has encountered an error while publishing this resource.

Error Type: Bad Request
Error Value: The ZGadflyDA product must be installed!"

What is the ZGadflyDA? I can't find a Debian package called that in my
available list...

If my questions are too elementary for this list, is their a Zope list,
specifically for newbies?

-- 
Stephen