YUM error - are repositories down or something?

[dave at tokyocomedy.com (Dave Gutteridge)]

Following advice on how to ensure that PHP and MySQL are on my machine
and working correctly, I ran the following YUM command, with the
subsequent error:

[root@localhost ~]# yum install php php-mysql httpd mysqlclient10 mysql-
server
Setting up Install Process
Setting up Repos
http://apt.sw.be/redhat/el4/en/i386/dag/repodata/repomd.xml: [Errno 4]
IOError: <urlopen error (113, 'No route to host')>
Trying other mirror.
Cannot open/read repomd.xml file for repository: dag
failure: repodata/repomd.xml from dag: [Errno 256] No more mirrors to
try.

Unless I am misunderstanding this error (which is quite likely), it
seems to indicate that YUM can not reach the online repositories. Is
that the case?

Or does the problem reside on my end?

Dave