The following test illustrates the problem.
script.py contains the line "1 / 0".
The 'bt' command is also wrong.

$ python3 -m pdb script.py
> /tmp/script.py(1)<module>()
-> 1 / 0
(Pdb) continue
Traceback (most recent call last):
  File "/usr/local/lib/python3.3/pdb.py", line 1651, in main
    pdb._runscript(mainpyfile)
  File "/usr/local/lib/python3.3/pdb.py", line 1532, in _runscript
    self.run(statement)
  File "/usr/local/lib/python3.3/bdb.py", line 405, in run
    exec(cmd, globals, locals)
  File "<string>", line 1, in <module>
  File "/tmp/script.py", line 1, in <module>
    1 / 0
ZeroDivisionError: division by zero
Uncaught exception. Entering post mortem debugging
Running 'cont' or 'step' will restart the program
> /tmp/script.py(1)<module>()
-> 1 / 0
(Pdb) up
> <string>(1)<module>()
(Pdb) up
> /usr/local/lib/python3.3/bdb.py(405)run()
-> exec(cmd, globals, locals)
(Pdb) up
> /usr/local/lib/python3.3/pdb.py(1532)_runscript()
-> self.run(statement)
(Pdb) up
> /usr/local/lib/python3.3/pdb.py(1651)main()
-> pdb._runscript(mainpyfile)
(Pdb) up
*** Oldest frame
(Pdb)