Connection to other side was lost in a non-clean fashion

Connection to other side was lost in a non-clean fashion

from scrapy.spider import BaseSpider
class dmozSpider(BaseSpider): name = "dmoz" allowed_domains = ["dmoz.org"]
start_urls = [
"http://www.dmoz.org/Computers/Programming/Languages/Python/Books/",
"http://www.dmoz.org/Computers/Programming/Languages/Python/Resources/" ]
def parse(self, response):
filename = response.url.split("/")[-2]
open(filename, 'wb').write(response.body)
then I run "scrapy crawl dmoz" then I got this error:
2013-09-14 13:20:56+0700 [dmoz] DEBUG: Retrying
http://www.dmoz.org/Computers/Programming/Languages/Python/Resources/>
(failed 1 times): Connection to other side was lost in a non-clean
fashion.
Does anyone know how to fix this?