apt-get update && apt-get install tklbam tklbam-squid-common tklbam-squid tklbam-python-boto tklbam-duplicity

TBH I'm not sure whether we need to list all the TKLBAM dependancies too but it won't hurt...

If that just says that they are all at the latest version; that's ok. Otherwise let them update and try again (as per above).

If that doesn't make any difference then the next thing that we could try is to exclude that particular path. You can test with this:

tklbam-backup --simulate -- -/var/spool/postfix/active/

If that works then try running it again without the '--simulate' switch...

FYI the "-- -/path" makes tklbam skip that path (and all the files & directories within it) but only for that session. Permanent overrides are set in /etc/tklbam/overrides