problem with 0.7.[34] which doesn't occur with 0.6.0

[dean gaudet]

with 0.7.3 & 0.7.4 i can successfully do this:

rdiff-backup twinlark-backup::/tmp testing

where testing is a new mirror, and i can increment it a bunch of times
without trouble.

but when i attempt a backup on top of a mirror which i've had going with
0.6.0 for months, i get this:

# rdiff-backup --change-source-perms --exclude-filelist exclude.list twinlark-backup::/ root
Traceback (most recent call last):
  File "/usr/bin/rdiff-backup", line 6154, in ?
    Globals.Main.Main()
  File "/usr/bin/rdiff-backup", line 5868, in Main
    self.take_action(rps)
  File "/usr/bin/rdiff-backup", line 5846, in take_action
    elif self.action == "backup": self.Backup(rps[0], rps[1])
  File "/usr/bin/rdiff-backup", line 5897, in Backup
    self.backup_init_select(rpin, rpout)
  File "/usr/bin/rdiff-backup", line 5911, in backup_init_select
    rpin.conn.Globals.set_select(DSRPath(1, rpin), self.select_opts)
  File "/usr/bin/rdiff-backup", line 1695, in __call__
    return apply(self.connection.reval, (self.name,) + args)
  File "/usr/bin/rdiff-backup", line 1631, in reval
    for arg in args: self._put(arg, req_num)
  File "/usr/bin/rdiff-backup", line 1398, in _put
    else: self._putobj(obj, req_num)
  File "/usr/bin/rdiff-backup", line 1402, in _putobj
    self._write("o", cPickle.dumps(obj, 1), req_num)
  File "/usr/lib/python2.2/copy_reg.py", line 57, in _reduce
    raise TypeError, "can't pickle %s objects" % base.__name__
TypeError: can't pickle file objects
#
Traceback (most recent call last):
  File "/usr/bin/rdiff-backup", line 6154, in ?
    Globals.Main.Main()
  File "/usr/bin/rdiff-backup", line 5868, in Main
    self.take_action(rps)
  File "/usr/bin/rdiff-backup", line 5845, in take_action
    PipeConnection(sys.stdin, sys.stdout).Server()
  File "/usr/bin/rdiff-backup", line 1619, in Server
    self.get_response(-1)
  File "/usr/bin/rdiff-backup", line 1593, in get_response
    self.answer_request(object, req_num)
  File "/usr/bin/rdiff-backup", line 1600, in answer_request
    arg_req_num, arg = self._get()
  File "/usr/bin/rdiff-backup", line 1492, in _get
    raise ConnectionReadError("Truncated header string (problem "
__main__.ConnectionReadError: Truncated header string (problem probably originated remotely)


mind you, this is the mirror which i stitched together from two other
mirrors as described a few days ago.  i can successfully use 0.6.0
against it though ...

any suggestions?

thanks
-dean