请教各位，准备在VOA的官网上正常mp3文件，在用 urllib2.urlopen()下载mp3类型文件时，报了 URLError。有可能是哪些原因造成的呢？多谢各位。

使用的代码如下：

 urllib2.urlopen('http://realaudio.rferl.org/voa/LERE/2013/07/19/6d07939b-45fc-4984-92b5-7f9ccc978ac5.mp3')

已经进行的一些尝试：

1. 链接是浏览器中是可以正常访问的。
2. 在chrome中修改user-agent为'aaa'，也可以正常下载，应该可以排除网站限制了非浏览器访问。
3. 下载html类型的链接正常。

感谢@依云的提醒，以下是Traceback:

 >>> urllib2.urlopen('http://realaudio.rferl.org/voa/LERE/2013/07/19/6d07939b-45fc-4984-92b5-7f9ccc978ac5.mp3')

Traceback (most recent call last):
  File "<pyshell#1>", line 1, in <module>
    urllib2.urlopen('http://realaudio.rferl.org/voa/LERE/2013/07/19/6d07939b-45fc-4984-92b5-7f9ccc978ac5.mp3')
  File "C:\Python27\lib\urllib2.py", line 127, in urlopen
    return _opener.open(url, data, timeout)
  File "C:\Python27\lib\urllib2.py", line 404, in open
    response = self._open(req, data)
  File "C:\Python27\lib\urllib2.py", line 422, in _open
    '_open', req)
  File "C:\Python27\lib\urllib2.py", line 382, in _call_chain
    result = func(*args)
  File "C:\Python27\lib\urllib2.py", line 1214, in http_open
    return self.do_open(httplib.HTTPConnection, req)
  File "C:\Python27\lib\urllib2.py", line 1187, in do_open
    r = h.getresponse(buffering=True)
  File "C:\Python27\lib\httplib.py", line 1045, in getresponse
    response.begin()
  File "C:\Python27\lib\httplib.py", line 409, in begin
    version, status, reason = self._read_status()
  File "C:\Python27\lib\httplib.py", line 365, in _read_status
    line = self.fp.readline(_MAXLINE + 1)
  File "C:\Python27\lib\socket.py", line 476, in readline
    data = self._sock.recv(self._rbufsize)
error: [Errno 10054]