shelve problem

[jim.vickroy]

I'm experiencing a problem with obtaining the list of keys in a
previously-created, shelve archive.  Note that I can ask if the archive
contains a particular key, but an exception is raised when I ask for the
list of all keys.

>>> import shelve
>>> db = shelve.open('d:/logs/products_journal')
>>> db.keys()
Traceback (most recent call last):
  File "<interactive input>", line 1, in ?
  File "C:\Python22\lib\shelve.py", line 56, in keys
    return self.dict.keys()
error: (22, 'Invalid argument')
>>> db.has_key('XPDIAG_20010514_172119758_AA_12.FTS')
1

I'm using Python 2.2 on a Win 2k platform.  Any ideas would be greatly
appreciated.