Yum update

Hello! I have a big problem with update....

This is the answer from the server when i write this command (of course as root!):

yum repolist all
ftp://ftp.redhat.com/pub/redhat/linux/beta/6Workstation/en/os/SRPMS/repodata/repomd.xml: [Errno 14] PYCURL ERROR 9 - "Server denied you to change to the given directory"
Trying other mirror.
repo id          repo name                                         status
rhel-source      Red Hat Enterprise Linux 6Workstation - i386 - So enabled: 2639
rhel-source-beta Red Hat Enterprise Linux 6Workstation Beta - i386 enabled:    0
virtualbox       RHEL/CentOS-6Workstation / i386 - VirtualBox      enabled:    0
 

And when i do yum update..

 yum update
ftp://ftp.redhat.com/pub/redhat/linux/beta/6Workstation/en/os/SRPMS/repodata/repomd.xml: [Errno 14] PYCURL ERROR 9 - "Server denied you to change to the given directory"
Trying other mirror.
Error: Cannot retrieve repository metadata (repomd.xml) for repository: rhel-source-beta. Please verify its path and try again
 

I think my repolist on /etc/yum.repos.d/ is corrupt or/and perhaps are wrong the keys on /etc/pki/rpm-gpg...

Someone can help me?

Thank you!!