SFS on Ubuntu Warty - authentication problems

Hi List,

I've been trying out SFS on Ubuntu Warty, but I've fallen at the first
hurdle: I can't even register a key! - I get config file errors for the
default config and authentication errors for key registering.

I've installed the sfs-server package on my workstation and the
sfs-client package inside a vmware on my workstation.

The sfsauthd_config file contains the following line, which appears to
give problems:
 Userfile -update -passwd -create -pub=sfs_users.pub sfs_users


With the config as-is, I start the sfs server in debug mode, and
sfsauthd fails with the following error:

 sfsauthd: /etc/sfs/sfsauthd_config:36: 'sfs_users' has -update flag;
 must end '.db/'
 sfsauthd: fatal: errors in config file
 sfsrwsd: version 0.8pre, pid 31020
 sfssd: EOF from /usr/lib/sfs-0.8pre/sfsauthd

which I assume explains why I then get a 'Connection refused' error when
doing an 'sfskey register' later.

I don't understand the error it gives - What must end '.db/'? I tried
appending .db/ to the filename...no good.

If I take comment this out in the config, it tells me it is using the
following config: 
  Userfile -passwd -update -create -pub=sfs_users.pub sfs_users

Once it is running (by commenting the line out before starting the
server), I run 'sfskey register' and follow the steps to generate the
key, but am then told 'access denied'.

The server gives me some kind of authentication error:
 sfsauthd: BAD login for newuser from LOCAL(uid=1003)!sfsauthd using 
 unix password (authentication database error)

Is this because it is trying to use the passwd file rather than shadow
or PAM?

Any help at all would be very much appreciated!

Thanks,
-Oli