我正在从云编码服务器（Koding.com）运行 Scrapy。我尝试使用教程来抓取 craigslist 广告，并在运行命令“scrapy crawl craigslist”时收到错误消息。有人可以解释错误信息吗？
2014-08-23 21:31:29+0000 [scrapy] INFO: Scrapy 0.14.4 started (bot: craigslist_sample)
2014-08-23 21:31:30+0000 [scrapy] DEBUG: Enabled extensions: LogStats, TelnetConsole, CloseSpider, WebService, CoreStats, MemoryUsage, SpiderState
Traceback (most recent call last):
File "/usr/bin/scrapy", line 4, in <module>
execute()
File "/usr/lib/python2.7/dist-packages/scrapy/cmdline.py", line 132, in execute
_run_print_help(parser, _run_command, cmd, args, opts)
File "/usr/lib/python2.7/dist-packages/scrapy/cmdline.py", line 97, in _run_print_help
func(*a, **kw)
File "/usr/lib/python2.7/dist-packages/scrapy/cmdline.py", line 139, in _run_command
cmd.run(args, opts)
File "/usr/lib/python2.7/dist-packages/scrapy/commands/crawl.py", line 43, in run
spider = self.crawler.spiders.create(spname, **opts.spargs)
File "/usr/lib/python2.7/dist-packages/scrapy/command.py", line 34, in crawler
self._crawler.configure()
File "/usr/lib/python2.7/dist-packages/scrapy/crawler.py", line 36, in configure
self.spiders = spman_cls.from_crawler(self)
File "/usr/lib/python2.7/dist-packages/scrapy/spidermanager.py", line 37, in from_crawler
return cls.from_settings(crawler.settings)
File "/usr/lib/python2.7/dist-packages/scrapy/spidermanager.py", line 33, in from_settings
return cls(settings.getlist('SPIDER_MODULES'))
File "/usr/lib/python2.7/dist-packages/scrapy/spidermanager.py", line 23, in __init__
for module in walk_modules(name):
File "/usr/lib/python2.7/dist-packages/scrapy/utils/misc.py", line 65, in walk_modules
submod = __import__(fullpath, {}, {}, [''])
File "/home/woshea/craigslist_sample/craigslist_sample/spiders/test.py", line 3, in <module>
from craigslist_sample.items import CraigslistSampleItem
File "/home/woshea/craigslist_sample/craigslist_sample/items.py", line 14