Description of problem:
Error occurs when running yum repolist 

Version-Release number of selected component:
yum-utils-1.1.31-4.fc17

Additional info:
cmdline:        /usr/bin/python /usr/bin/package-cleanup --orphans
executable:     /usr/bin/package-cleanup
kernel:         3.7.9-104.fc17.x86_64
uid:            1000

Truncated backtrace:
subprocess.py:1249:_execute_child:OSError: [Errno 8] Exec format error

Traceback (most recent call last):
  File "/usr/bin/package-cleanup", line 400, in <module>
    util = PackageCleanup()
  File "/usr/bin/package-cleanup", line 60, in __init__
    self.main()
  File "/usr/bin/package-cleanup", line 362, in main
    for po in sorted(self.doPackageLists(pkgnarrow='extras').extras):
  File "/usr/lib/python2.7/site-packages/yum/__init__.py", line 2735, in doPackageLists
    avail = self.pkgSack.simplePkgList(patterns=patterns,
  File "/usr/lib/python2.7/site-packages/yum/__init__.py", line 1013, in <lambda>
    pkgSack = property(fget=lambda self: self._getSacks(),
  File "/usr/lib/python2.7/site-packages/yum/__init__.py", line 779, in _getSacks
    self.repos.populateSack(which=repos)
  File "/usr/lib/python2.7/site-packages/yum/repos.py", line 343, in populateSack
    urlgrabber.grabber.parallel_wait()
  File "/usr/lib/python2.7/site-packages/urlgrabber/grabber.py", line 2259, in parallel_wait
    start(opts, 1)
  File "/usr/lib/python2.7/site-packages/urlgrabber/grabber.py", line 2148, in start
    dl.start(opts)
  File "/usr/lib/python2.7/site-packages/urlgrabber/grabber.py", line 2080, in start
    dl = _ExternalDownloader()
  File "/usr/lib/python2.7/site-packages/urlgrabber/grabber.py", line 2003, in __init__
    stdout = subprocess.PIPE,
  File "/usr/lib64/python2.7/subprocess.py", line 679, in __init__
    errread, errwrite)
  File "/usr/lib64/python2.7/subprocess.py", line 1249, in _execute_child
    raise child_exception
OSError: [Errno 8] Exec format error

Local variables in innermost frame:
errread: None
c2pread: 7
gc_was_enabled: True
errwrite: None
shell: False
errpipe_write: 10
executable: '/usr/libexec/urlgrabber-ext-down'
close_fds: False
self: <subprocess.Popen object at 0x102c990>
env: None
cwd: None
child_exception: OSError(8, 'Exec format error')
args: ['/usr/libexec/urlgrabber-ext-down']
fd: None
c2pwrite: 8
data: 'cexceptions\nOSError\np0\n(I8\nS\'Exec format error\'\np1\ntp2\nRp3\n(dp4\nS\'child_traceback\'\np5\nS\'Traceback (most recent call last):\\n  File "/usr/lib64/python2.7/subprocess.py", line 1201, in _execute_child\\n    os.execvp(executable, args)\\n  File "/usr/lib64/python2.7/os.py", line 344, in execvp\\n    _execvpe(file, args)\\n  File "/usr/lib64/python2.7/os.py", line 368, in _execvpe\\n    func(file, *argrest)\\nOSError: [Errno 8] Exec format error\\n\'\np6\nsb.'
creationflags: 0
errpipe_read: 9
preexec_fn: None
p2cread: 5
startupinfo: None
p2cwrite: 6
universal_newlines: False