Bueno pues resulta que al querer actualizar con yum -y update me aparece lo siguiente:
[root@gruporisc risc]# yum -y update
There was a problem importing one of the Python modules
required to run yum. The error leading to this problem was:
No module named sqlitecachec
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:
2.6.4 (r264:75706, Jun 4 2010, 18:20:16)
[GCC 4.4.4 20100503 (Red Hat 4.4.4-2)]
If you cannot solve this problem yourself, please go to
the yum faq at:
http://yum.baseurl.org/wiki/Faq
y no se que hacer
alguien me puede decir 
)