Yum Update error in FreePBX Distro

[root@localhost ~]# yum update
Loaded plugins: fastestmirror, kmod
Loading mirror speeds from cached hostfile
http://yum.freepbxdistro.org/centos/5/addons/i386/repodata/repomd.xml: [Errno 4] IOError: <urlopen error (-2, ‘Name or service not known’)>
Trying other mirror.
http://yum.freepbxdistro.org/centos/5/os/i386/repodata/repomd.xml: [Errno 4] IOError: <urlopen error (-2, ‘Name or service not known’)>
Trying other mirror.
http://packages.digium.com/centos/5/current/i386/repodata/repomd.xml: [Errno 4] IOError: <urlopen error (-2, ‘Name or service not known’)>
Trying other mirror.
http://yum.freepbxdistro.org/centos/5/extras/i386/repodata/repomd.xml: [Errno 4] IOError: <urlopen error (-2, ‘Name or service not known’)>
Trying other mirror.
http://yum.freepbxdistro.org/centos/5/updates/i386/repodata/repomd.xml: [Errno 4] IOError: <urlopen error (-2, ‘Name or service not known’)>
Trying other mirror.
Setting up Update Process
No Packages marked for Update

It appears your yum cache is outdated.

Do a yum clean all from the command line