Aha! Mystery solved (since OP finally figured out the time zone "at fault"). I found this:
http://www.timeanddate.com/worldclock/timezone.html?n=60&syear=1980
1980 No time changes
1981 No time changes
1982 No time changes
1983 No time changes
1984 Time zone change on Friday, March 16, 1984 at 1:00:00 AM
1985 Time zone change on Tuesday, December 31, 1985 at 11:00:00 PM
1986 No time changes
1987 No time changes
1988 No time changes
1989 No time changes
So, I guess the answer to "What happened on March 16th 1984" is that Casablanca changed its time at 1:00 AM that day. :)
And technically, it jumped immediately from midnight to 1:00 AM, so probably all times starting at 00:00 and just before 01:00 will produce the same error. That is, my guess is that time.mktime((1984,3,16,1,0,0,0,0,0))
and greater will work, but for example, time.mktime((1984,3,16,0,59,0,0,0,0))
will not.