Error in shelve, keys() returns invalid argument...bug?

[wolf at one.net]

I'm trying to use the shelve module in Win98SE in Python 1.52, and I
can create the shelf just fine, but when I try to get the keys for the
shelf it gives me an error. Here's a screen dump:

C:\APPS\Thief's Quest>"C:\Program Files\Python\PYTHON.EXE"
Python 1.5.2 (#0, Apr 13 1999, 10:51:12) [MSC 32 bit (Intel)] on win32
Copyright 1991-1995 Stichting Mathematisch Centrum, Amsterdam
>>> import shelve
>>> SavedGame = shelve.open("Test.psg")
>>> SavedGame
<shelve.DbfilenameShelf instance at 79b120>
>>> SavedGame.keys
<method Shelf.keys of DbfilenameShelf instance at 79b120>
>>> SavedGame.keys()
Traceback (innermost last):
  File "<stdin>", line 1, in ?
  File "C:\Program Files\Python\Lib\shelve.py", line 55, in keys
    return self.dict.keys()
bsddb.error: (22, 'Invalid argument')
>>>

Am I doing something wrong? Or does the shelve module need an
additional module in Win98 that doesn't come with the base install?

Any help would be appreciated!
Respectfully,

Wolf

"The world is my home, it's just that some rooms are draftier than
others". -- Wolf