Setting up Update Process
Setting up repositories
not using ftp, http[s], or file for repos, skipping - 4 is not a valid release or hasnt been released yet
Cannot find a valid baseurl for repo: update
Error: Cannot find a valid baseurl for repo: update
大意是说，此目录已经没有任何价值了，因为CentOS-4已经停止发布了...要找到一个源repo