http://anorien.csc.warwick.ac.uk/mirrors/centos/5.3/os/i386/repodata/repomd.xml: [Errno 14] HTTP Error 404: Not Found
Trying other mirror.
http://ftp.heanet.ie/pub/centos/5.3/os/i386/repodata/repomd.xml: [Errno 14] HTTP Error 404: Not Found
Trying other mirror.
http://mirror.as29550.net/mirror.centos.org/5.3/os/i386/repodata/repomd.xml: [Errno 14] HTTP Error 404: Not Found
Trying other mirror.
http://mirror.bytemark.co.uk/centos/5.3/os/i386/repodata/repomd.xml: [Errno 14] HTTP Error 404: Not Found
Trying other mirror.
http://mirror.sov.uk.goscomb.net/centos/5.3/os/i386/repodata/repomd.xml: [Errno 14] HTTP Error 404: Not Found
Trying other mirror.
http://mirror.ukhost4u.com/centos/5.3/os/i386/repodata/repomd.xml: [Errno 14] HTTP Error 404: Not Found
Trying other mirror.
http://mirrors.dedipower.com/centos/5.3/os/i386/repodata/repomd.xml: [Errno 14] HTTP Error 404: Not Found
Trying other mirror.
http://mirrors.nl.kernel.org/centos/5.3/os/i386/repodata/repomd.xml: [Errno 14] HTTP Error 404: Not Found
Trying other mirror.
http://mirrors.ukfast.co.uk/sites/ftp.centos.org/5.3/os/i386/repodata/repomd.xml: [Errno 14] HTTP Error 404: Not Found
Trying other mirror.
http://www.mirrorservice.org/sites/mirror.centos.org/5.3/os/i386/repodata/repomd.xml: [Errno 14] HTTP Error 404: Not Found
Trying other mirror.
Error: Cannot retrieve repository metadata (repomd.xml) for repository: base. Please verify its path and try again
yum clean all
and then ran the desired yum command again.