Before you can do anything related to the BaBar software, you have to make sure your SLAC UNIX account is set up properly. If you don't have an account there, there are detailed instructions about how to get one on the Web.
Briefly, there are two steps: you need to make sure you are listed in the Babar
Membership Database, and if you are, then you can apply for a SLAC UNIX account. After you get it, you can check that it works by logging into SLAC machines from here (I usually use morgan04.slac.stanford.edu). Once you have a SLAC account you should also get an AFS account. The safest thing to do is to log into any SLAC machine, type ``movetoafs'' and then log out and wait till the next day (the transfer to AFS usually happens automatically at midnight). After this, your home directory at SLAC should be something like:
/afs/slac.stanford.edu/u/ec/your_user_name.
Now, at UCSB, if everything went ok, you should be able to type ``klog'' on electron (which is our AFS machine), type in your SLAC password when prompted for it, and get access to SLAC AFS system.
If you encounter problems at any stage of getting a SLAC account, the best person to contact (in my opinion) is Tom Glanzman (DRAGON@SLAC.Stanford.EDU).