[Zope] Zope crashes on request of certain page

[Sven Jacobs]

> You read the installation instructions for "VerboseSecurity".
> 
> It (hopefully) tells you that you have to activate Python
> implemented Zope Security,

I extracted the archive into the Products directory of the instance 
home. The product now is listed under installed products.

> to reconfigure the "error_log" object (to not ignore "Unauthorized"
> exceptions) and then to look in the "error_log" object for
> information about the resulting "Unauthorized" exception.

The readme just tells me

> Just remove "Unauthorized" from the list of ignored exceptions.

I have no idea where to find this list. Is it a config file or somehwere 
hidden within the management interface of Zope?

Also there is no error_log file. Not in var nor in log.