问题：

There was a problem importing one of the Python modules
required to run yum. The error leading to this problem was:
   No module named yum
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:
2.5.4 (r254:67916, Feb 24 2010, 10:03:49) 
[GCC 4.1.2 20080704 (Red Hat 4.1.2-44)]
If you cannot solve this problem yourself, please go to 
the yum faq at:
  http://wiki.linux.duke.edu/YumFaq

解决：

将/usr/bin/yum中#/usr/bin/python 改为：/usr/bin/python2.4

sed -i ‘s/#\/usr\/bin\/python/#\/usr\/bin\/python2.4/g‘  /usr/bin/yum