Is this a bug in multiprocessing or in my script?

[erikcw]

Hi,

I'm trying to get multiprocessing to working consistently with my
script.  I keep getting random tracebacks with no helpful
information.  Sometimes it works, sometimes it doesn't.

Traceback (most recent call last):
  File "scraper.py", line 144, in <module>
    print pool.map(scrape, range(10))
  File "/usr/lib/python2.6/multiprocessing/pool.py", line 148, in map
    return self.map_async(func, iterable, chunksize).get()
  File "/usr/lib/python2.6/multiprocessing/pool.py", line 422, in get
    raise self._value
TypeError: expected string or buffer

It's not always the same traceback, but they are always short like
this.  I'm running Python 2.6.2 on Ubuntu 9.04.

Any idea how I can debug this?

Thanks!
Erik