AFS is the Andrew File System and on PDSF there is full AFS access only on the interactive nodes. PDSF is part of the NERSC cell so to use some other cell you must specify the cell you want. For example, to use the rhic cell you would do
klog -cell rhic
and if your AFS username is not the same as your PDSF username you would need to specify that as well:
klog -cell rhic -principal <your_AFS_username>
AFS clients are running on the batch system but since there is no clean and secure way to propagate your token to the batch nodes you have read-only access to the AFS area.
Note that the default machine type is "i386_linux24" (this is used to do the translation of the @ symbol) which may not be what you want. There isn't a clean way to change this on a user by user basis so if this is causing problems for you please file a ticket for assistance.