2011/2/15 Sébastien Sablé <report@bugs.python.org>:
..
>>>> for t in (-2, -1, 0, 1):
> ...     print(time.localtime(t))
> ...
> time.struct_time(tm_year=1970, tm_mon=1, tm_mday=1, tm_hour=0, tm_min=59, tm_sec=58, tm_wday=3, tm_yday=1, tm_isdst=0)
..

This looks right. (For time.timezone = -3600.)   I actually suspected
that you were east of Greenwich.   My hypothesis is that AIX localtime
implementation adjusts t -> t - timezone before computing broken down
time and thus fails to detect that localtime() is given negative
argument.  If my hypothesis is correct, time.gmtime(-1) should fail on
your system.

..
> TZ=NFT-1DFT,M3.5.0,M10.5.0
>
> which is strange since NFT seems to be in Australia.

In your TZ setting, the UTC offset and DST rules are specified
explicitly, so it does not matter what names are given to the
timezones for most time calculations.