CentOS - Mar 2010 - Yum errors on a new install

Hi all;

I'm getting this the first time I try and run yum update on a new install of
CentOS 5.4 (x86_64):


Error: requested datatype primary not available


My internet connection is working
a 'yum clean all'  does not help


[root at localhost ~]# yum clean all
Loaded plugins: fastestmirror
Cleaning up Everything
Cleaning up list of fastest mirrors

[root at localhost ~]# yum update
Loaded plugins: fastestmirror
Determining fastest mirrors
 * addons: mirror.fdcservers.net
 * base: mirror.fdcservers.net
 * extras: mirrors.serveraxis.net
 * updates: mirrors.bluehost.com
addons                                                                        
|  509 B     00:00     
Error: requested datatype primary not available


thoughts?

thanks in advance...