You are using Centos 5 which is deprecated so nothing in yum will work until you follow this post to use the vault:
http://realtechtalk.com/Centos_59_Working_Vault_Repo_file-1921-articles
yum update
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* epel: fedora-archive.ip-connect.vn.ua
Traceback........
OpenVZ has made vzctl version 4.7 default to using ploop which is a big annoyance. No one wants it otherwise we'd use Xen or KVM.
Make sure to manually specify vzctl 4.6.1 or you will have issues with old scripts breaking since it defaults to using ploop (a single image like Xen/KVM).
Here's a list to old versions of vzctl.........