You need to authenticate with the authentication server of the Andrew File System (AFS) before you can access files on it. This is done using the klog program.
If your username on AFS is the same as the username you are using on your computer:
If your username on AFS is different, say afs-joe, then use this:
$ klog -principal afs-joe
In either case, you will be asked for your password. Use the password that works with AFS, not your local password.
Tried with: Ubuntu 12.04.1 LTS