help with strange traceback while unpickling on 2.0b2

[Tom]

I'm running a script on Python v2.0b2 that unpickles data from a text file.
I get the traceback included below.
What I find unusual is that there is the text "(imPyObj 2" at the end of the
traceback, instead of an error message.
(My pickle file does contain the text "(imPyObj", but not the "2".)
Also note that the script is still (sort of) running after the traceback,
but it seems to have gone off to la-la land so I have to press Ctrl-C to
stop it.

Any suggestions?

Tom.

Traceback (most recent call last):
  File "x:\Dev\mGui.py", line 555, in OnIdle
    EventMan.ProcessInput();
  File "x:\Dev\mGui.py", line 38, in ProcessInput
    Event = Port.ReceiveEvent();
  File "x:\Dev\mPorts.py", line 29, in ReceiveEvent
    Event = self.pick.load()
  File "e:\Python\Python20\lib\pickle.py", line 516, in load
    dispatch[key](self)
  File "e:\Python\Python20\lib\pickle.py", line 783, in load_get
    self.append(self.memo[self.readline()[:-1]])
 (imPyObj 2