samba - Dec 2013 - error "rsync: connection unexpectedly closed (0 bytes received so far)"

G'day Sambaites,

I'm trying to use rsync to backup from one machine to another. I'm
getting an error "rsync: connection unexpectedly closed (0 bytes
received so far)" and I don't know where to go from here.

I'm running the rsync daemon on machine starker. I'm trying to backup
from another machine to it. For testing, I'm just trying to backup one
file. The command line I'm using is:
  /usr/local/bin/rsync -vvvv local/etc/smb.conf rsync://starker:/backup/Wed

The full output is:
  opening tcp connection to starker port 873
  Connected to starker (xx.xx.xx.xx)
  sending daemon args: --server -vvvve.L . backup/Wed  (4 args)
  (Client) Protocol versions: remote=31, negotiated=31
  [sender] make_file(smb.conf,*,0)
  [sender] flist start=0, used=1, low=0, high=0
  [sender] i=0 local/etc smb.conf mode=0100444 len=788 flags=0
  send_file_list done
  [sender] flist_eof=1
  file list sent
  send_files starting
  rsync: connection unexpectedly closed (0 bytes received so far) [sender]
  [sender] _exit_cleanup(code=12, file=io.c, line=226): entered
  rsync error: error in rsync protocol data stream (code 12) at
io.c(226) [sender=3.1.0]
  [sender] _exit_cleanup(code=12, file=io.c, line=226): about to call
exit(12)

On the receiver machine, rsyncd.conf contains:
  [backup]
        path = /backup
        comment = Backup directory
Running
  rsync starker::
correctly lists the backup module
  backup          Backup directory

Does anybody have any clues, please?

Thanks,
    Graham