[Tutor] Shelve error

[Robert Moloney]

I keep getting this error I think it might be to do with the size of the
file 

>>> sh = shelve.open("searchPhrase")
>>> sh.keys()
Traceback (innermost last):
  File "<stdin>", line 1, in ?
  File "/usr/lib/python1.5/shelve.py", line 55, in keys
    return self.dict.keys()
bsddb.error: (22, 'Invalid argument')
>>> sh["http://rory.calhoone.ie/manual/sections.html"]           
['Help']
>>> 

I can access individual key values but it won't give me a list of keys

Please Help 

Rob