problemas con Yum

[Reinier en METUNAS]

hola listeros, tengo lios al usar el yum, no he podido actualizar, me da
este error!. al aprecer no puede abrir o leer el archivo
alguna sugerencia?.
saludos
reinier


[root en server ~]# yum update
Setting up Update Process
Setting up repositories
update                    100% |=========================|  951 B    00:00
base                      100% |=========================| 1.1 kB    00:00
addons                    100% |=========================|  951 B    00:00
extras                    100% |=========================| 1.1 kB    00:00
Reading repository metadata in from local files
primary.xml.gz            100% |=========================|  80 kB    00:17
update    : ################################################## 252/252
Added 252 new packages, deleted 0 old in 1.87 seconds
primary.xml.gz            100% |=========================| 344 kB    02:57
http://mirror.centos.org/centos/4/os/i386/repodata/primary.xml.gz: [Errno 4]
Soc
Trying other mirror.
Error: failure: repodata/primary.xml.gz from base: [Errno 256] No more
mirrors try.

----------------------------------------------------------------------------
------------
[root en server~]# yum -y install dhcp
Setting up Install Process
Setting up repositories
Cannot open/read repomd.xml file for repository: update
failure: repodata/repomd.xml from update: [Errno 256] No more mirrors to
try.
Error: failure: repodata/repomd.xml from update: [Errno 256] No more mirrors
to try.