Error under Cygwin - threading module

[AdSR]

Hello,

Nothing relevant found on Google for this, so I'm asking here. I wrote
a short script that launches several threads (parallel download using
urllib.urlretrieve in this case). Sometimes when I launch my script
under Cygwin, I get strange error messages like:

      2 [win] python 1912 Winmain: Cannot register window class

Sometimes all of the threads run OK, otherwise after the "correct"
ones finish the console stops responding anyway. No problems directly
under Windows, and /lib/python2.3/test/test_threading.py works fine
too. What is wrong?

Here is the script:

---- wp_retr.py ----

#!/usr/bin/env python

"""Retrieve files from the list, give new names if present in list."""

from __future__ import division

import re
import urllib
import threading
import time
import sys


class Download:
    def __init__(self, url, name):
        self.url = url
        self.name = name
        self.last_check = 0.0


class DownloadBag:
    def __init__(self, downloads):
        self._downloads = []
        for url, name in downloads:
            self._downloads.append(Download(url, name))
    def start(self):
        threads = []
        for d in self._downloads:
            p = self._createProgress(d)
            thargs = (d.url, d.name, p)
            th = threading.Thread(target=urllib.urlretrieve,
args=thargs)
	    threads.append(th)
            th.start()
	return threads
    def _progress(self, download, blocks, blk_size, total):
        t = time.time()
        if t - download.last_check > 5:
            if total != -1:
                print "%s -> %s: %2.1f%%" % (download.url,
download.name,
                                            
blocks*blk_size/total*100)
            else:
                print "%s -> %s: %d bytes" % (download.url,
download.name,
                                              blocks*blk_size)
            download.last_check = t
    def _createProgress(self, download):
        def progf(blocks, blk_size, total):
            self._progress(download, blocks, blk_size, total)
        return progf


if __name__ == "__main__":
    spcre = re.compile(r"(.*?)\s+(.*)$")
    slashre = re.compile(r"(?:.*)/(.*?)$")
    f = file(sys.argv[1]) #"filelist.txt")
    filelist = []
    for line in f:
        line = line.strip()
        m = spcre.match(line)
        if m:
            url, name = m.groups()
        else:
            m = slashre.match(line)
            if m:
                url, name = line, m.group(1)
            else:
                print "Incorrect line format:\n%s" % line
                continue
        filelist.append((url, name))
    f.close()
    db = DownloadBag(filelist)
    threads = db.start()
    for t in threads:
        t.join() 

----

and here is an example input file (run as python filelist.py
filelist.txt):

---- filelist.txt ----

http://www.gnu.org/software/bash/manual/bashref.html
http://www.gnu.org/software/make/manual/html_mono/make.html 

----

TIA,

AdSR