[CentOS] What is wrong with yum?

Hello,

in my CentOS-Base.repo file there is a line
baseurl=http://mirror.centos.org/centos/$releasever/updates/$basearch
and yum update said 'nothing to do'. Then I change this line to
baseurl=http://mirror.centos.org/centos/5.1/updates/i386 and yum
updates firefox, squid, sos and so on. That happens on two of my
computers, reproducible.

Does yum sometimes forget it's release version?


regards
Olaf