升级不成功啊。请大家帮我看看----软件升级失败

苦涩之恋

.20 [8161kB]
Get:186 http://mirror.centos.org centos/4/apt/i386/os xorg-x11-tools 6.8.2-1.EL.13.20 [518kB]
Get:187 http://mirror.centos.org centos/4/apt/i386/os xorg-x11-twm 6.8.2-1.EL.13.20 [341kB]
Fetched 351MB in 55m35s (105kB/s)
Committing changes...
Preparing...                ########################################### [100%]
        file /etc/sysconfig/rhn/sources from install of up2date-4.4.50-4.centos4 conflicts with file from package redhat-release-4AS-2.4
E: Error while running transaction
You have new mail in /var/spool/mail/root
这是什么缘故啊？？/请赐教