I have a VPS running CentOS 5 and I was always running yum to update its software. This went ok until few days ago when “yum update” brought this :
There was a problem importing one of the Python modules
required to run yum. The error leading to this problem was:No module named cElementTree
Please install a package which provides this module, or
verify that the module is installed correctly.It’s possible that the above module doesn’t match the
current version of Python, which is:
~~~~~~If you cannot solve this problem yourself, please go to
the yum faq at:http://wiki.linux.duke.edu/YumFaq
After around an hour I saw that an easy fix for the Python issue required gcc installed .. but it wasn’t installed 
so I searched for another solution, even simpler :
wget http://archives.fedoraproject.org/pub/archive/fedora/linux/core/6/i386/os/Fedora/RPMS/python-elementtree-1.2.6-5.i386.rpm
rpm -Uvh –oldpackage python-elementtree-1.2.6-5.i386.rpm
That fixed it! 
(the first thing to run was yum install gcc)
Hope this will help someone
Best wishes
Sorin
this is raw data,
————-
# yum
There was a problem importing one of the Python modules
required to run yum. The error leading to this problem was:
No module named cElementTree
Please install a package which provides this module, or
verify that the module is installed correctly.
It’s possible that the above module doesn’t match the
current version of Python, which is:
2.4.3 (#1, Sep 3 2009, 15:37:37)
[GCC 4.1.2 20080704 (Red Hat 4.1.2-46)]
If you cannot solve this problem yourself, please go to
the yum faq at:
http://wiki.linux.duke.edu/YumFaq
# rpm -q python-elementtree
python-elementtree-1.2.6-7.el4.rf
# rpm -q –whatrequires python-elementtree
yum-3.2.22-26.el5.centos
# wget
http://packages.sw.be/python-elementtree/python-elementtree-1.2.6-7.el5.test.x86_64.rpm
–2010-07-27 03:46:33–
http://packages.sw.be/python-elementtree/python-elementtree-1.2.6-7.el5.test.x86_64.rpm
Resolving packages.sw.be… 85.13.226.40
Connecting to packages.sw.be|85.13.226.40|:80… connected.
HTTP request sent, awaiting response… 302 Found
Location:
http://rpmforge.sw.be/redhat/el5/en/x86_64/test/RPMS/python-elementtree-1.2.6-7.el5.test.
x86_64.rpm [following]
–2010-07-27 03:46:34–
http://rpmforge.sw.be/redhat/el5/en/x86_64/test/RPMS/python-elementtree-1.2.6-7.el5.test.
x86_64.rpm
Resolving rpmforge.sw.be… 85.13.226.40
Connecting to rpmforge.sw.be|85.13.226.40|:80… connected.
HTTP request sent, awaiting response… 200 OK
Length: 103806 (101K) [application/x-rpm]
Saving to: `python-elementtree-1.2.6-7.el5.test.x86_64.rpm’
100%[======================================>] 103,806 41.5K/s in 2.4s
2010-07-27 03:46:38 (41.5 KB/s) – `python-elementtree-1.2.6-7.el5.test.x86_64.rpm’ saved
[103806/103806]
# ls
python-elementtree-1.2.6-7.el5.test.x86_64.rpm
# rpm -Uvh python-elementtree-1.2.6-7.el5.test.x86_64.rpm
Preparing… ########################################### [100%]
1:python-elementtree ########################################### [100%]
thats was easy :_
——————
puyeng, you save me. thx so much!
Thank you very much