[mod_python] Vampire does not support packages?

I'm moving a Vampire site from one machine (Debian "etch") to another
(Debian "lenny"). I installed Vampire 1.8 on the new machine but the
site now fails with a puzzling error message:

MOD_PYTHON ERROR

ProcessId:      32531
Interpreter:    'devel.codev-nic.generic-nic.net'

ServerName:     'devel.codev-nic.generic-nic.net'
DocumentRoot:   '/var/www/devel.codev-nic.generic-nic.net'

URI:            '/details'
Location:       None
Directory:      '/var/www/devel.codev-nic.generic-nic.net/'
Filename:       '/var/www/devel.codev-nic.generic-nic.net/details'
PathInfo:       ''

Phase:          'PythonHandler'
Handler:        'vampire'

Traceback (most recent call last):

  File "/usr/lib/python2.5/site-packages/mod_python/importer.py", line 1537, in HandlerDispatch
    default=default_handler, arg=req, silent=hlist.silent)

  File "/usr/lib/python2.5/site-packages/mod_python/importer.py", line 1229, in _process_target
    result = _execute_target(config, req, object, arg)

  File "/usr/lib/python2.5/site-packages/mod_python/importer.py", line 1128, in _execute_target
    result = object(arg)

  File "/usr/lib/python2.5/site-packages/vampire/lookup.py", line 709, in _handler
    module = _import(req,file)

  File "/usr/lib/python2.5/site-packages/vampire/lookup.py", line 54, in _import
    module = _moduleCache.importModule(name,directory,req)

  File "/usr/lib/python2.5/site-packages/vampire/cache.py", line 316, in importModule
    execfile(file,module.__dict__)

  File "/var/www/devel.codev-nic.generic-nic.net/details.py", line 23, in <module>
    from Site import Site

  File "/usr/lib/python2.5/site-packages/vampire/cache.py", line 518, in load_module
    return importModule(fullname,self.__directory,self.__req)

  File "/usr/lib/python2.5/site-packages/vampire/cache.py", line 316, in importModule
    execfile(file,module.__dict__)

  File "/var/www/devel.codev-nic.generic-nic.net/Site.py", line 23, in <module>
    from SiteLogic import SiteLogic

  File "/usr/lib/python2.5/site-packages/vampire/cache.py", line 518, in load_module
    return importModule(fullname,self.__directory,self.__req)

  File "/usr/lib/python2.5/site-packages/vampire/cache.py", line 316, in importModule
    execfile(file,module.__dict__)

  File "/var/www/devel.codev-nic.generic-nic.net/SiteLogic.py", line 2, in <module>
    from codevnic.lib.Config import Config

  File "/usr/lib/python2.5/site-packages/vampire/cache.py", line 518, in load_module
    return importModule(fullname,self.__directory,self.__req)

  File "/usr/lib/python2.5/site-packages/vampire/cache.py", line 179, in importModule
    raise ImportError("Vampire does not support packages.")

ImportError: Vampire does not support packages.