[CentOS] Problem YUM Centos 5

Fri Oct 30 15:43:45 UTC 2009
Adriano Frare <alfrare at e-alinux.com>

Dear Friends,

Today , I ran command yum update and  I received follow error below.

======================= BEGIN =========
Loaded plugins: fastestmirror
Determining fastest mirrors
Traceback (most recent call last):
  File "/usr/bin/yum", line 29, in ?
    yummain.user_main(sys.argv[1:], exit_code=True)
  File "/usr/share/yum-cli/yummain.py", line 229, in user_main
    errcode = main(args)
  File "/usr/share/yum-cli/yummain.py", line 104, in main
    result, resultmsgs = base.doCommands()
  File "/usr/share/yum-cli/cli.py", line 343, in doCommands
    return self.yum_cli_commands[self.basecmd].doCommand(self, 
self.basecmd, self.extcmds)
  File "/usr/share/yum-cli/yumcommands.py", line 554, in doCommand
    return base.search(extcmds)
  File "/usr/share/yum-cli/cli.py", line 691, in search
    for (po, keys, matched_value) in matching:
  File "/usr/lib/python2.4/site-packages/yum/__init__.py", line 1593, in 
searchGenerator
    for sack in self.pkgSack.sacks.values():
  File "/usr/lib/python2.4/site-packages/yum/__init__.py", line 591, in 
<lambda>
    pkgSack = property(fget=lambda self: self._getSacks(),
  File "/usr/lib/python2.4/site-packages/yum/__init__.py", line 434, in 
_getSacks
    self.repos.populateSack(which=repos)
  File "/usr/lib/python2.4/site-packages/yum/repos.py", line 223, in 
populateSack
    self.doSetup()
  File "/usr/lib/python2.4/site-packages/yum/repos.py", line 71, in doSetup
    self.ayum.plugins.run('postreposetup')
  File "/usr/lib/python2.4/site-packages/yum/plugins.py", line 176, in run
    func(conduitcls(self, self.base, conf, **kwargs))
  File "/usr/lib/yum-plugins/fastestmirror.py", line 181, in 
postreposetup_hook
    all_urls = FastestMirror(all_urls).get_mirrorlist()
  File "/usr/lib/yum-plugins/fastestmirror.py", line 333, in get_mirrorlist
    self._poll_mirrors()
  File "/usr/lib/yum-plugins/fastestmirror.py", line 376, in _poll_mirrors
    pollThread.start()
  File "/usr/lib/python2.4/threading.py", line 416, in start
    _start_new_thread(self.__bootstrap, ())
thread.error: can't start new thread
============= END =========================


How I do solve it?

Thnaks

Adriano