tklbam-backup failed last night.  From the trace below, I assume this means mail either came in or out while my backup was running.  Do I need to exclude the /var/spool/exim4 directory?  I re-ran the backup by hand and it completed successfully.

/etc/cron.daily/tklbam-backup:

Traceback (most recent call last):
  File "/usr/bin/tklbam-backup", line 266, in <module>
    main()
  File "/usr/bin/tklbam-backup", line 237, in main
    b = backup.Backup(conf)
  File "/usr/lib/tklbam/backup.py", line 251, in __init__
    self._create_extras(extras_paths, profile_paths, conf)
  File "/usr/lib/tklbam/backup.py", line 229, in _create_extras
    conf.overrides.fs)
  File "/usr/lib/tklbam/backup.py", line 211, in _write_whatchanged
    changes = whatchanged(dirindex, paths)
  File "/usr/lib/tklbam/changes.py", line 240, in whatchanged
    changes += [ Change.Overwrite(path) for path in new + edited ]
  File "/usr/lib/tklbam/changes.py", line 72, in __init__
    self.uid = self.stat.st_uid
  File "/usr/lib/tklbam/changes.py", line 47, in stat
    self._stat = os.lstat(self.path)
OSError: [Errno 2] No such file or directory: '/var/spool/exim4/input/1SlKAA-0001YE-6R-H'
run-parts: /etc/cron.daily/tklbam-backup exited with return code 1