IOError: [Errno 32] Broken pipe

# -*- coding: utf-8 -*-
#!/usr/bin/python26

from SimpleHTTPServer import SimpleHTTPRequestHandler  
from BaseHTTPServer import BaseHTTPRequestHandler  
from BaseHTTPServer import HTTPServer  
import SocketServer
import cgi
import os
import logging
import thread


class MyHTTPRequestHandler( BaseHTTPRequestHandler ):  

    def do_GET( self ):  
        pass

    def do_POST(self):

        # 创建线程执行命令    
        thread.start_new_thread(self.callscript, ('cd /home/www/man-sphinx/docs.500.com/html && /usr/bin/sphinx-build -c ./  ./  /home/www/html/docs.500.com/html/',))

        form = cgi.FieldStorage(  # cgi.FieldStorage实例效果类似一个字典，包含键－值和len等内置函数
            fp=self.rfile,
            headers=self.headers,
            environ={'REQUEST_METHOD':'POST',
                     'CONTENT_TYPE':self.headers['Content-Type'],
                     })

        self.send_response(200)
        self.end_headers()
        self.wfile.write('Client: %s\n' % str(self.client_address))
        # self.wfile.write('User-agent: %s\n' % str(self.headers['user-agent']))
        # self.wfile.write('Path: %s\n' % self.path)

        params = {}
        for field in form.keys():
            params[field] = form[field].value

        filepath = params.get('f')
        data = params.get('d')
        code = params.get('c')
        user = params.get('u')

        try:
            result = self.filesave(filepath, data, code, user)
        except Exception, e:
            result = 'Error in filesave:%s' % e
        finally:
            self.wfile.write(result)

        # self.callscript('cd /home/www/man-sphinx/docs.500.com/html && /usr/bin/sphinx-build -c ./  ./  /home/www/html/docs.500.com/html/')

    def filesave(self, filepath, data, code, user):

        if (filepath and data and code and user) is None:
            return 'Params uncomplete!\n'

        path = '/'.join(filepath.split('/')[:-1])
        name = filepath.split('/')[-1]
        if not os.path.exists(path):
            os.makedirs(path)
        f = open(filepath, 'w')
        f.write(data.decode(code).encode('utf-8'))
        f.close()
        self.log(filepath, user)
        return 'Filesaved in %s' % filepath

    def callscript(self, command):
        try:
            os.popen(command)  # 报错
        except Exception,e:
            print 'Error in CallScript:%s' % e


    def log(self, filepath, user):
        pass

    def do_HEAD( self ):  
        pass  


if __name__ == '__main__':  
    port = 28080  

    handler = SimpleHTTPRequestHandler  

    #httpd = SocketServer.TCPServer(("", port ), handler )  
    httpd = HTTPServer(('', port ), MyHTTPRequestHandler)  

    print "Server is running at port", port  
    httpd.serve_forever() 
这是一个简单的文件存储服务器，文件存储工作正常，但是我希望接受post请求的时候开启一个线程去刷新文件目录，问题是在callscript函数里使用os.popen()会报题示的错误，如果改成os.system()就不会. 详细错误：

全选复制放进笔记# Sphinx version: 1.1.3
# Python version: 2.6.5
# Docutils version: 0.11 release
# Jinja2 version: 2.7.1
Traceback (most recent call last):
  File "/usr/lib/python2.6/site-packages/Sphinx-1.1.3-py2.6.egg/sphinx/cmdline.py", line 188, in main
    warningiserror, tags)
  File "/usr/lib/python2.6/site-packages/Sphinx-1.1.3-py2.6.egg/sphinx/application.py", line 94, in __init__
    self.info(bold('Running Sphinx v%s' % sphinx.__version__))
  File "/usr/lib/python2.6/site-packages/Sphinx-1.1.3-py2.6.egg/sphinx/application.py", line 238, in info
    self._status.flush()

IOError: [Errno 32] Broken pipe