[Zope] How To Get A Zope Traceback

[Tom Purl]

I'm having a problem importing a Plone site into Zope.  To determine 
whether it's a Zope problem or a Plone problem, I'm trying to get a 
traceback.

When I import the site, I get the following error page:

--------
Zope Error

Zope has encountered an error while publishing this resource.

Error Type: KeyError
Error Value: navigation_tree_slot

Troubleshooting Suggestions

     * This resource may be trying to reference a nonexistent object or 
variable navigation_tree_slot.
     * The URL may be incorrect.
     * The parameters passed to this resource may be incorrect.
     * A resource that this resource relies on may be encountering an error.

For more detailed information about the error, please refer to the HTML 
source for this page.

If the error persists please contact the site maintainer. Thank you for 
your patience.
--------

There isn't any tracback information in the web page or its source.  I 
then took a look at the following two log files:

Z2.log
Z2-detailed.log

...but neither had any traceback information.  Is there something that 
I'm missing?

Thank you,

Tom Purl