I have the same problem on Fedora 17 with
deja-dub-20.2
duplicity-0.6.18

DUPLICITY: DEBUG 1
DUPLICITY: . Selecting /home/jan/Documents/CITY/reading/xan-22-3-321.pdf

DUPLICITY: DEBUG 1
DUPLICITY: . Comparing ('home', 'jan', 'Documents', 'CITY', 'reading', 'xan-22-3-321.pdf') and None

DUPLICITY: DEBUG 1
DUPLICITY: . Getting delta of (('home', 'jan', 'Documents', 'CITY', 'reading', 'xan-22-3-321.pdf') /home/jan/Documents/CITY/reading/xan-22-3-321.pdf reg) and None

DUPLICITY: INFO 4 'home/jan/Documents/CITY/reading/xan-22-3-321.pdf'
DUPLICITY: . A home/jan/Documents/CITY/reading/xan-22-3-321.pdf

DUPLICITY: INFO 11
DUPLICITY: . AsyncScheduler: running task synchronously (asynchronicity disabled)

DUPLICITY: INFO 1
DUPLICITY: . Writing smb://ENTERPRISE;XXXXXXXXXX@samba1/homes/backup/duplicity-full.20121112T172651Z.vol23.difftar.gz

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

DUPLICITY: DEBUG 1
DUPLICITY: . Backtrace of previous error: Traceback (innermost last):
DUPLICITY: .   File "/usr/lib64/python2.7/site-packages/duplicity/backend.py", line 311, in iterate
DUPLICITY: .     return fn(*args, **kwargs)
DUPLICITY: .   File "/usr/lib64/python2.7/site-packages/duplicity/backends/giobackend.py", line 119, in copy_file
DUPLICITY: .     target.get_parse_name())
DUPLICITY: .   File "/usr/lib64/python2.7/site-packages/duplicity/backends/giobackend.py", line 95, in handle_error
DUPLICITY: .     raise e
DUPLICITY: .  Error: Success
DUPLICITY: . 

DUPLICITY: INFO 1
DUPLICITY: . Writing smb://ENTERPRISE;XXXXXXX@samba1/homes/backup/duplicity-full.20121112T172651Z.vol23.difftar.gz

DUPLICITY: WARNING 1
DUPLICITY: . Attempt 2 failed: Error: Success

DUPLICITY: DEBUG 1
DUPLICITY: . Backtrace of previous error: Traceback (innermost last):
DUPLICITY: .   File "/usr/lib64/python2.7/site-packages/duplicity/backend.py", line 311, in iterate
DUPLICITY: .     return fn(*args, **kwargs)
DUPLICITY: .   File "/usr/lib64/python2.7/site-packages/duplicity/backends/giobackend.py", line 119, in copy_file
DUPLICITY: .     target.get_parse_name())
DUPLICITY: .   File "/usr/lib64/python2.7/site-packages/duplicity/backends/giobackend.py", line 95, in handle_error
DUPLICITY: .     raise e
DUPLICITY: .  Error: Success
DUPLICITY: . 

DUPLICITY: INFO 1
DUPLICITY: . Writing smb://ENTERPRISE;XXXXXXX@samba1/homes/backup/duplicity-full.20121112T172651Z.vol23.difftar.gz

DUPLICITY: WARNING 1
DUPLICITY: . Attempt 3 failed: Error: Success

DUPLICITY: DEBUG 1
DUPLICITY: . Backtrace of previous error: Traceback (innermost last):
DUPLICITY: .   File "/usr/lib64/python2.7/site-packages/duplicity/backend.py", line 311, in iterate
DUPLICITY: .     return fn(*args, **kwargs)
DUPLICITY: .   File "/usr/lib64/python2.7/site-packages/duplicity/backends/giobackend.py", line 119, in copy_file
DUPLICITY: .     target.get_parse_name())
DUPLICITY: .   File "/usr/lib64/python2.7/site-packages/duplicity/backends/giobackend.py", line 95, in handle_error
DUPLICITY: .     raise e
DUPLICITY: .  Error: Success
DUPLICITY: . 

DUPLICITY: INFO 1
DUPLICITY: . Writing smb://ENTERPRISE;XXXXXXX@samba1/homes/backup/duplicity-full.20121112T172651Z.vol23.difftar.gz

DUPLICITY: WARNING 1
DUPLICITY: . Attempt 4 failed: Error: Success

DUPLICITY: DEBUG 1
DUPLICITY: . Backtrace of previous error: Traceback (innermost last):
DUPLICITY: .   File "/usr/lib64/python2.7/site-packages/duplicity/backend.py", line 311, in iterate
DUPLICITY: .     return fn(*args, **kwargs)
DUPLICITY: .   File "/usr/lib64/python2.7/site-packages/duplicity/backends/giobackend.py", line 119, in copy_file
DUPLICITY: .     target.get_parse_name())
DUPLICITY: .   File "/usr/lib64/python2.7/site-packages/duplicity/backends/giobackend.py", line 95, in handle_error
DUPLICITY: .     raise e
DUPLICITY: .  Error: Success
DUPLICITY: . 

DUPLICITY: INFO 1
DUPLICITY: . Writing smb://ENTERPRISE;XXXXXXXX/homes/backup/duplicity-full.20121112T172651Z.vol23.difftar.gz

DUPLICITY: ERROR 50 put '/tmp/duplicity-6bAHwS-tempdir/mktemp-a1uEvO-2' 'smb://ENTERPRISE;XXXXXXXX@samba1/homes/backup/duplicity-full.20121112T172651Z.vol23.difftar.gz'
DUPLICITY: . Success

DUPLICITY: DEBUG 1
DUPLICITY: . Removing still remembered temporary file /tmp/duplicity-6bAHwS-tempdir/mkstemp-yolxxz-1

DUPLICITY: DEBUG 1
DUPLICITY: . Removing still remembered temporary file /tmp/duplicity-6bAHwS-tempdir/mktemp-a1uEvO-2