使用scrapy startproject tutorial时，执行错误：

 scrapy startproject tutorial
Traceback (most recent call last):
  File "/usr/local/bin/scrapy", line 5, in <module>
    from pkg_resources import load_entry_point
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources.py", line 2603, in <module>
    working_set.require(__requires__)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources.py", line 666, in require
    needed = self.resolve(parse_requirements(requirements))
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources.py", line 565, in resolve
    raise DistributionNotFound(req)  # XXX put more info here
pkg_resources.DistributionNotFound: queue lib

去/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources.py中查看它的代码， 在565行左右：

while requirements:
            req = requirements.pop(0)   # process dependencies breadth-first
            if req in processed:
                # Ignore cyclic or redundant dependencies
                continue
            dist = best.get(req.key)
            if dist is None:
                # Find the best distribution and add it to the map
                dist = self.by_key.get(req.key)
                if dist is None:
                    if env is None:
                        env = Environment(self.entries)
                    dist = best[req.key] = env.best_match(req, self, installer)
                    if dist is None:
                        raise DistributionNotFound(req)  # XXX put more info here
                to_activate.append(dist)
            if dist not in req:
                # Oops, the "best" so far conflicts with a dependency
                raise VersionConflict(dist,req) # XXX put more info here
            requirements.extend(dist.requires(req.extras)[::-1])
            processed[req] = True

不太清楚具体环境哪里错误了，还请各位大神或者有过类似经验的