Comment 2 for bug 229826

You need to quote the target, at least, because it contains a space: 'ssh://User Name@localhost:/home/username/Backup' - or has this been cleaned by apport during report?

Anyway, the bug is still valid, because it should not crash, but report a sane error, if the port cannot get parsed. (I've looked not at the source code yet), but it looks like it parsed the URL wrong:
    File "/usr/lib/python2.5/site-packages/duplicity/urlparse_2_5.py", line 116, in port
      return int(port, 10)
  ValueError: invalid literal for int() with base 10: ''