Backup to smb NTFS share aborts after a while (can not write *.vol1300.difftar.gpg)

[Thierry Bonifas]

Ubuntu 12.04.2 LTS

deja-dup 22.0-0ubuntu3
duplicity 0.6.18-0ubuntu3.1

Dejadup aborts after 31,7 GB copied with the quite disturbing message in german:

Datensicherung Fehlgeschlagen
Erfolg

(= Backup failed
 Success)

There are exactly 1300 files in the NTFS (Win7) directory and writing more fails, coincidence?
There is enough space left (ca 200GB)
All retries abort the same way.

Interesting part from dejadup.log:

DUPLICITY: INFO 1
DUPLICITY: . Schreibe smb://stebs/dejadup/duplicity-full.20130228T175429Z.vol1300.difftar.gpg

DUPLICITY: WARNING 1
DUPLICITY: . Attempt 1 failed: Error: Erfolg

DUPLICITY: DEBUG 1
DUPLICITY: . Backtrace of previous error: Traceback (innermost last):
DUPLICITY: . File "/usr/lib/python2.7/dist-packages/duplicity/backend.py", line 311, in iterate
DUPLICITY: . return fn(*args, **kwargs)
DUPLICITY: . File "/usr/lib/python2.7/dist-packages/duplicity/backends/giobackend.py", line 119, in copy_file
DUPLICITY: . target.get_parse_name())
DUPLICITY: . File "/usr/lib/python2.7/dist-packages/duplicity/backends/giobackend.py", line 95, in handle_error
DUPLICITY: . raise e
DUPLICITY: . Error: Erfolg