[Samba] samba-tool dbcheck uncaught exception

[basti]

Hello,
my domain is

Dns domain  = foo
Realm 	= FOO
Workgroup	= FOO


samba-tool dbcheck --cross-ncs --fix -v

....
Checking object DC=foo
ERROR(<type 'exceptions.ValueError'>): uncaught exception - unable to
parse dn string
  File "/usr/lib/python2.7/dist-packages/samba/netcmd/__init__.py", line
175, in _run
    return self.run(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/samba/netcmd/dbcheck.py", line
136, in run
    controls=controls, attrs=attrs)
  File "/usr/lib/python2.7/dist-packages/samba/dbchecker.py", line 141,
in check_database
    error_count += self.check_object(object.dn, attrs=attrs)
  File "/usr/lib/python2.7/dist-packages/samba/dbchecker.py", line 1509,
in check_object
    expected_dn = ldb.Dn(self.samdb, "RDN=RDN,%s" % (parent_dn))