There was a problem importing one of the Python modules
required to run yum. The error leading to this problem was:

   /usr/lib64/libcurl.so.4: undefined symbol: ldap_init_fd

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:
2.6.6 (r266:84292, Nov 22 2013, 12:16:22)
[GCC 4.4.7 20120313 (Red Hat 4.4.7-4)]

If you cannot solve this problem yourself, please go to
the yum faq at:
  http://yum.baseurl.org/wiki/Faq

mkdir ~/RPMS/
wget http://ftp.riken.jp/Linux/centos/6.1/updates/x86_64/Packages/curl-7.19.7-26.el6_1.2.x86_64.rpm
wget http://ftp.riken.jp/Linux/centos/6.1/updates/x86_64/Packages/libcurl-7.19.7-26.el6_1.2.x86_64.rpm
sudo rpm -Uvh --oldpackage *.rpm