yum- has the http location changed?

[Rolli Adam E Civ 917 CF/SCBN <Adam Rolli BARKSDALE AF MIL>]

I was using yum last friday to update /install apps and it worked fine.
Today I get:

Gathering header information file(s) from server(s)
Server: Fedora Core 1 - i386 - Base
retrygrab() failed for:
  http://fedora.redhat.com/releases/fedora-core-1/headers/header.info
  Executing failover method
failover: out of servers to try
Error getting file
http://fedora.redhat.com/releases/fedora-core-1/headers/header.info
[Errno 4] IOError: HTTP Error 404: Not Found

and I did export my proxy to the env. otherwise I would get a 403 error
Has the HTTP location changed for the site?
Thanks
Adam