Hello guys.. I'm a new Amanda user..

I have just installed Amanda on my VMWare (CentOS based) yesterday and it went smoothly.
However, today I found out that I cannot access /etc/amanda. The folder has been missing.

I already tried to reinstall Amanda using "yum -y install amanda*", but it failed.
The output was :
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
Could not retrieve mirrorlist [url]http://mirrorlist.centos.org/[/url]....
[Errno 4] IOError: <urlopen error (-3, 'Temporary failure in name resolution')
Error: Cannot find a valid baseurl for repo: base

I have no idea how to fix it..
Is there anyone can give me an advice or guidance?
Any comments or help is highly appreciated.
Thank you.