[Zope-CMF] Product registration error in registerDirectory for directory with open permissions

[J C Lawrence]

I'm getting the following traceback from the __init__ for a CMF product
I'm working on:

Traceback (most recent call last):
  File "/usr/lib/zope/lib/python/OFS/Application.py", line 531, in import_product
    product=__import__(pname, global_dict, global_dict, silly)
  File "/var/lib/zope/Products/CalTopic/__init__.py", line 35, in ?
    registerDirectory( 'skins/caltopic', globals() )
  File "/var/lib/zope/Products/CMFCore/DirectoryView.py", line 329, in registerDirectory
    self.registerDirectoryByPath(filepath, subdirs)
  File "/var/lib/zope/Products/CMFCore/DirectoryView.py", line 334, in registerDirectoryByPath
    self._directories[fp] = di = DirectoryInformation(normfilepath, fp)
  File "/var/lib/zope/Products/CMFCore/DirectoryView.py", line 62, in __init__
    for entry in _filtered_listdir(expanded_fp):
  File "/var/lib/zope/Products/CMFCore/DirectoryView.py", line 46, in _filtered_listdir
    listdir(path))
OSError: [Errno 2] No such file or directory: '/var/lib/zope/Products/CalTopic/skins/caltopic'

The problem is that /var/lib/zope/Products/CalTopic/skins/caltopic both
exists and is world readable:

  $ ls -l 
  $ ls -l /var/lib/zope/Products/CalTopic/skins/
  total 2
  drwxr-xr-x    2 claw     claw          624 Jun 30 22:15 caltopic
  ...

The contents of the directory are 0644.

I'm a bit lost as to why I'm getting the above traceback.  Ideas?

-- 
J C Lawrence                
---------(*)                Satan, oscillate my metallic sonatas. 
claw@kanga.nu               He lived as a devil, eh?		  
http://www.kanga.nu/~claw/  Evil is a name of a foeman, as I live.