[FC 5] probème YUM

Bonjour,
j'ai un problème d'utilisation de yum.
Par exemple, lorsque je veux installer n'importe quel paquet (ici xmms), j'obtiens.

[root@ER0005 ~]# yum install xmms
Loading "installonlyn" plugin
Setting up Install Process
Setting up repositories
core [1/3]
Traceback (most recent call last):
File "/usr/bin/yum", line 29, in ?
yummain.main(sys.argv[1:])
File "/usr/share/yum-cli/yummain.py", line 97, in main
result, resultmsgs = do()
File "/usr/share/yum-cli/cli.py", line 474, in doCommands
return self.installPkgs()
File "/usr/share/yum-cli/cli.py", line 837, in installPkgs
self.doRepoSetup()
File "/usr/share/yum-cli/cli.py", line 78, in doRepoSetup
yum.YumBase.doRepoSetup(self, thisrepo=thisrepo)
File "/usr/lib/python2.4/site-packages/yum/__init__.py", line 248, in doRepoSetup
repo.baseurlSetup()
File "/usr/lib/python2.4/site-packages/yum/repos.py", line 530, in baseurlSetup
mirrorurls = getMirrorList(self.mirrorlist, self.proxy_dict)
File "/usr/lib/python2.4/site-packages/yum/repos.py", line 839, in getMirrorList
fo = urlresolver.urlopen(url, proxies=pdict)
File "/usr/lib/python2.4/site-packages/urlgrabber/grabber.py", line 583, in urlopen
return default_grabber.urlopen(url, **kwargs)
File "/usr/lib/python2.4/site-packages/urlgrabber/grabber.py", line 741, in urlopen
return self._retry(opts, retryfunc, url)
File "/usr/lib/python2.4/site-packages/urlgrabber/grabber.py", line 702, in _retry
r = apply(func, (opts,) + args, {})
File "/usr/lib/python2.4/site-packages/urlgrabber/grabber.py", line 740, in retryfunc
return URLGrabberFileObject(url, filename=None, opts=opts)
File "/usr/lib/python2.4/site-packages/urlgrabber/grabber.py", line 893, in __init__
self._do_open()
File "/usr/lib/python2.4/site-packages/urlgrabber/grabber.py", line 960, in _do_open
fo, hdr = self._make_request(req, opener)
File "/usr/lib/python2.4/site-packages/urlgrabber/grabber.py", line 1059, in _make_request
fo = opener.open(req)
File "/usr/lib/python2.4/urllib2.py", line 358, in open
response = self._open(req, data)
File "/usr/lib/python2.4/urllib2.py", line 376, in _open
'_open', req)
File "/usr/lib/python2.4/urllib2.py", line 337, in _call_chain
result = func(*args)
File "/usr/lib/python2.4/urllib2.py", line 573, in <lambda>
lambda r, proxy=url, type=type, meth=self.proxy_open: \
File "/usr/lib/python2.4/urllib2.py", line 580, in proxy_open
if '@' in host:
TypeError: iterable argument required
[root@ER0005 ~]#

Merci de votre aide.