[Zope] problem moving ZODB to new Z

[Darran Edmundson]

Hi Zopesters,

We have just migrated from a machine running
Zope with the ZServer to a different machine
running Zope with an Apache web server.  But 
we have a problem, namely, after copying over 
the Data.fs ZODB to the new site, Zope cannot
find a needed (but installed) product (Navigator).

This product definitely exists:
/Zope-2.1.0-src/lib/python/Products/Navigator
so why is Zope not seeing it?
i
From the manager view of the ZODB:

Product at /optics / Control_Panel / Products / Navigator  
There are currently no items in Installed product Navigator (Navigator
Product, Version 1.02)  

Any help is much appreciated as my site is off-line
until I can fix this problem.

Cheers,
Darran.