google for "centos error performing checksum" refers to createrepo but of course "yum install createrepo" also fails and the instructions appear to be overkill. Is there a "simple" soultion? here's the result of yum update: # yum -v update Loading "fastestmirror" plugin Config time: 0.118 Yum Version: 3.2.22 Setting up Package Sacks Loading mirror speeds from cached hostfile * base: mirror.science.uottawa.ca * extras: mirror.science.uottawa.ca * rpmforge: ftp-stud.fht-esslingen.de * updates: mirror.science.uottawa.ca rhel-src/primary | 1.1 MB 00:02 ftp://ftp.redhat.com/pub/redhat/linux/enterprise/5Server/en/os/SRPMS/repodata/primary.xml.gz: [Errno -3] Error performing checksum Trying other mirror. Error: failure: repodata/primary.xml.gz from rhel-src: [Errno 256] No more mirrors to try. and for repolist # yum repolist Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile * base: mirror.science.uottawa.ca * extras: mirror.science.uottawa.ca * rpmforge: ftp-stud.fht-esslingen.de * updates: mirror.science.uottawa.ca rhel-src/primary | 1.1 MB 00:02 ftp://ftp.redhat.com/pub/redhat/linux/enterprise/5Server/en/os/SRPMS/repodata/primary.xml.gz: [Errno -3] Error performing checksum Trying other mirror. Error: failure: repodata/primary.xml.gz from rhel-src: [Errno 256] No more mirrors to try. TIA -- This message has been scanned for viruses and dangerous content by Avantel Systems, and is believed to be clean.