I had a simmilar problem, but I'm using Squeak in Linux & Solaris, I'malmost sure that the problem has something to do with timezone, 'couse I'm in GNT+3 and I have a 3 hours difference in Squeak's clock, is there some fix to this problem?
Timezones have been causing problems for Unix for a while (ever since the arrival of HP-UX -- sorry, I couldn't resist ;). Richie Bielak has been doing some serious investigation into this, and he sent me some patches a couple of days ago which I haven't had chance to test out on multiple platforms yet. (Trouble is, as far as daylight savings are concerned, it can take up to 6 months to discover that "it isn't quite right yet". ;)
One thing that he found to improve the situation was explicitly calling tzset(), something that I was hitherto foolishly trusting to work like the manual page claims:
DESCRIPTION The tzset() function initializes the tzname variable from the TZ environment variable. This function is automatically called by the other time conversion functions that depend on the time zone.
Live and learn...
Ian