yum fails with the error : " ImportError: No module named cElementTree"

Issue

• yum update fails with the error below:

  # yum update
  Plugin "refresh-packagekit" can't be imported
  Loaded plugins: rhnplugin, security
  Traceback (most recent call last):
    File "/usr/bin/yum", line 29, in <module>
      yummain.user_main(sys.argv[1:], exit_code=True)
  [...]
    File "/usr/lib/python2.6/site-packages/yum/misc.py", line 1169, in cElementTree_iterparse
      _cElementTree_import()
    File "/usr/lib/python2.6/site-packages/yum/misc.py", line 1164, in _cElementTree_import
      import cElementTree
  ImportError: No module named cElementTree
  

• yum repolist fails with error below:

  # yum repolist
  Plugin "refresh-packagekit" can't be imported
  Loaded plugins: rhnplugin, security
  Traceback (most recent call last):
    File "/usr/bin/yum", line 29, in <module>
      yummain.user_main(sys.argv[1:], exit_code=True)
  [...]
    File "/usr/lib/python2.6/site-packages/yum/misc.py", line 1169, in cElementTree_iterparse
      _cElementTree_import()
    File "/usr/lib/python2.6/site-packages/yum/misc.py", line 1164, in _cElementTree_import
      import cElementTree
  ImportError: No module named cElementTree