Thank you Mark342,
I follow your suggestion :
Try reinstalling pygtk.
Test it.
Then reinstall GTK+2.0
Test it.
Do one then the other so that, if it works, we know which package fixes it.
none of them solve the problem, but after the reinstalling gtk+2.0-2.20.0-1pclos2010, there are more error error occured, the pygobject :
[blackhole@localhost ~]$ ccsm
Could not find platform dependent libraries <exec_prefix>
Consider setting $PYTHONHOME to <prefix>[:<exec_prefix>]
Traceback (most recent call last):
File "/usr/bin/ccsm", line 32, in <module>
import gtk
File "/usr/lib/python2.5/site-packages/gtk-2.0/gtk/__init__.py", line 30, in <module>
import gobject as _gobject
ImportError: No module named gobject
blackhole@localhost ~]$
Does simple-ccsm work? (you can find it in the repository, the command to launch it is simple-ccsm)
nope, the error message is :
[blackhole@localhost ~]$ simple-ccsm
Could not find platform dependent libraries <exec_prefix>
Consider setting $PYTHONHOME to <prefix>[:<exec_prefix>]
Traceback (most recent call last):
File "/usr/bin/simple-ccsm", line 23, in <module>
import subprocess
File "/usr/lib/python2.5/subprocess.py", line 401, in <module>
import select
ImportError: No module named select
[blackhole@localhost ~
It seems the updates or me

borked the installation. hiks

but I'm pretty sure even if I'm reinstall from fresh, this problem will keep coming back after update.
How can I resintall or reconfigure the python just like from the fresh installation ?
Where is exactly the $PYTHONHOME point or refering to ?
thank you