I installed something and now my yum dont work:

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, 15:37:12)
[GCC 4.1.2 20080704 (Red Hat 4.1.2-46)]

i use CentOS release 5.4 (2.6.18-164.2.1.el5.028stab066.7 #1 SMP Tue Dec 1 23:22:32 EET 2009 i686 i686 i386 GNU/Linux) on my VPS.

# rpm -qa --last shows:

python-elementtree-1.2.6-5 Wed 24 Mar 2010 12:56:46 PM EET
rpmforge-release-0.5.1-1.el3.rf Wed 24 Mar 2010 08:20:32 AM EET
perl-Convert-ASN1-0.22-1.el3.rf Wed 24 Mar 2010 08:20:31 AM EET
rsync-3.0.7-1.el3.rf Wed 24 Mar 2010 08:20:30 AM EET
gpg-pubkey-e42d547b-3960bdf1 Wed 24 Mar 2010 08:15:57 AM EET
gpg-pubkey-6b8d79e6-3f49313d Wed 24 Mar 2010 08:15:57 AM EET
gpg-pubkey-1aa78495-3eb24301 Wed 24 Mar 2010
08:15:57 AM EET

also # rpm -q yum -> yum-3.2.22-20.el5.centos
# rpm -q python -> python-2.4.3-27.el5
rpm -q python-elementtree -> python-elementtree-1.2.6-7.el5.rf

i think that this problem are with python, how solve this problem? I dont want reinstall VPS.

Since the problem shows that you don't have the CElementTree module, I'd suggest you install an RPM that has that module.
You can try this one.
http://rpm.pbone.net/index.php3/stat....i386.rpm.html
I'm not sure if that will help but it's what I'd do in that situation.
I suspect that the required module is not available in you repositories. So you may be able to solve your problem by adding a suitable repository.

I still have this problem. Maybe you can exactly say what to do and how can i solve this problem this yum?

My suggestion is, go to the page in the link. Download the rpm package there. Then, on you computer, goto downloads with your file browser and double click on the package you downloaded to install it. Then test to see if yum is working.
you can also find rpm packages for most things at that site if a particular package you need isn't yummable.
disclaimer: although I have used that site without problems in the past. I do have anything to do with that site and I cant be held responsible for any badwear you might get from there.

What did you install??????
you do know that rf is incompatible with almost every other cent repo !!!!!
If you use rf then YOU ONLY use rf .
by incompatible i mean that rf can KILL a cent install if you are not VERY VERY careful

So how to fix now yum and my system? In my /etc/yum.repos.d i have:
-rw-r--r-- 1 root root 2323 Mar 17 2009 CentOS-Base.repo
-rw-r--r-- 1 root root 626 Oct 1 2009 CentOS-Media.repo
-rw-r--r-- 1 root root 190 Feb 2 19:11 vz.repo

if i run: rpm -qa | grep rpmforge i can't find anything... and if i run python and type import yum i have this error:

Python 2.4.3 (#1, Sep 3 2009, 15:37:12)
[GCC 4.1.2 20080704 (Red Hat 4.1.2-46)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import yum
Traceback (most recent call last):
File "<stdin>", line 1, in ?
File "/usr/lib/python2.4/site-packages/yum/__init__.py", line 49, in ?
import comps
File "/usr/lib/python2.4/site-packages/yum/comps.py", line 22, in ?
import CElementTree
ImportError: No module named CElementTree
>>>

why are you trying to run yum from python ?

to see what repos are installed run thin
from a normal bash terminal
you might want to read the ceno os wiki
http://wiki.centos.org/
and the page for adding repos
http://wiki.centos.org/AdditionalResources/Repositories

as to fixing ????
it looks like this might have been the problem
"python-elementtree"

yum uses python and any change to it ( outside of what is in the centOS repo) can and will mess it up.

--
also why did you try to install this

rpmforge-release-0.5.1-1.el3.rf
perl-Convert-ASN1-0.22-1.el3.rf
rsync-3.0.7-1.el3.rf
the "el3" means it is for RHEL 3 NOT RHEL 5
this is FOR CENT 3 " rpmforge-release-0.5.1-1.el3.rf" NOT CentOS 5.4
--
and the rpm search would be for *.rt
if you did manage to install a bunch of cent 3 programs on cent 5 it might NOT be fixable
uninstall any rf and ALL el3 rpm's

i cant run yum repolist all, i get the same error:

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, 15:37:12)
[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


i uninstalled all .rf and el3 rpm's, but i still have the same error when i want run yum. Maybe i need reinstall python or yum? Or change some python files?

you will also need to reinstall EVERY rt and el3 rpm with the correct el5 rpm from the Cent repo


by making changes to python and installing the wrong ( el3) rpm's the system might be beyond help.

we would need to see just how many and what were installed
the output from rpm would be nice
if more than two or 3 *.el3 rpm's were installed the computer might not be fixable.
But it also depends on what the packages are
if one of the rt's ( or el3's)were a critical system files ...
This is not easily fixed .

there is no output for rpm -qa | grep rt -- and this -- rpm -qa | grep el now.

maybe i need change some python files or reinstall it? How to fix my system?

the rt is a typo it is rf ( rpmforge)

what do you mean there is no out put for these two commands you DID install some files for red hat 3 and some files from rpmforge

I already fixed yum.

Hey Vitasis,
I am a newbie to linux and getting the same problem as yours.
Can you tell me how you fixed your yum.
Please.