Centos4 has come to an end of life, please refer EOL notification for Centos4.x found at
http://lwn.net/Articles/484756/ Errors now occur when updating due to CentOS-4 having been copied to the CentOS Vault (
http://vault.centos.org/4.9/) and subsequent emptying of the CentOS-4.8 and 4.9 trees from the CentOS mirrors.
The sme 7.5 server base and updates repositories do not point to the Centos Vault location, and as a result, updating of SME server version 7.xx from server-manager or the command line using standard commands is no longer possible. SME Developers are considering a number of options, a fix is expected soon.
In the meantime,
users should update their servers manually from the command line using the following command:
yum --disablerepo=base --disablerepo=updates update
Progress about this issue can be found at Bugzilla:
http://bugs.contribs.org/show_bug.cgi?id=6868SME8 RC1 is expected to be released soon, all users are encouraged to test and become familiar with the new version. To this end, please download the latest Beta version (8.0b7). Additional information can be found here:
http://wiki.contribs.org/SME_Server_8
Please report any bugs to Bugzilla.