yum upgrade of centos to 5.4 conflicts with exim

[thechronic]

this solves the following error:

error: open of /var/cache/yum/base/packages/setup-2.5.37-4.el4_8.1.noarch.rpm failed: No such file or directory

cd /var/cache/yum/base/packages/
yum install yum-utils.noarch
yumdownloader setup
rpm -Uvh --force setup-2.5.37-4.el4_8.1.noarch.rpm