Postfix suddenly started crashing....

Hi People....
Last week I upgraded postfix to 2.0.16 (from 2.0.11). Everything went fine
and the new postfix worked well. However this week postfix has started to
have some problems. I was hoping that someone could give me a lead as to
what they are or some sort of handle on starting the debug process.....

The first sign of trouble is the fast flush service breaking down. I start
to see log lines like this:

Jan 26 20:17:27 [postfix/pipe] warning: 6FD53C9487: defer service failure
Jan 26 20:17:27 [postfix/pipe] warning: unable to talk to fast flush service

Soon other things, including the python filter I wrote then start to break
down:

Jan 26 20:17:42 [postfix/cleanup] warning: connect #1 to subsystem
private/rewrite: Connection refused
Jan 26 20:17:44 [postfix/pipe] warning: 965ADC9488: defer service failure
Jan 26 20:17:44 [postfix/pipe] warning: unable to talk to fast flush service
Jan 26 20:17:50 [postfix/smtp] warning: premature end-of-input on
private/py-saf socket while reading input attribute name
Jan 26 20:17:50 [postfix/smtp] warning: private/py-saf socket: malformed
response

Eventually postfix just dies and it's restarted:

Jan 26 20:24:25 [postfix/smtpd] warning: postmaster notify: Connection
refused
Jan 27 01:24:29 [postfix/postqueue] warning: Mail system is down --
accessing queue directly
- Last output repeated twice -
Jan 26 20:32:02 [postfix-sa/postfix-script] stopping the Postfix mail system
Jan 26 20:32:02 [postfix-sa/master] terminating on signal 15
Jan 26 20:32:02 [postfix/postfix-script] fatal: the Postfix mail system is
not running
Jan 26 20:33:47 [postfix/postfix-script] starting the Postfix mail system
Jan 26 20:33:48 [postfix/master] daemon started -- version 2.0.16

I noted that there is one line in there that has *totaly* the wrong time on
it. In the intrest of not snowing you folks with logs I have just included
the intresting looking warning lines. If there is any extra info that I can
provide, let me know and I will.

Postfix ver: 2.0.16
Distro: Gentoo 1.4 x86

Naturally this has all started to happen on the last day of work before I go
on holiday for a week :( life has a 'funny' sence of humor.

If anyone can give me any advice, links or other leads on this problem I
would appreciate it.... this has happened four times today so far...

Many thanks....

Nick