That would explain the significance of the number of transactions.
> Could the file be getting opened without 'rb'?
>

Austine,

You're probably already testing this, but if not, please
test with these lines in FileStorage.__init__():

        if readonly:
             self.fp = open(self.filename, 'rb')
         else:
             self.fp = open(self.filename, 'a+b')