[CentOS] C5 krb5 updates do not get applied

Hi,

the latest Centos 5 krb5 1.6.1-17.el5_1.1 do not get applied to any of
my servers. I can see the updates being available on the mirror
servers, but "yum update" shows nothing. The krb5 updates for Centos 4
were installed on all of my Centos 4 servers without any problem. Does
somebody have any idea what could cause the problem on Centos 5?

Thanks in advance,
Bernd.