Sunbird Stymied by Win XP Daylight Savings Reset

I run Sunbird from a dedicated data partition and run several XP's from the same HD using bootitng partition and boot manager.

Suddenly Sunbird couldn't remember the hour being set in a new appointment and would always change it to 11:00.

I found that this only happened from one of the XP's.

I narrowed it down to this:

It happens if the Windows Clock's "Automatically Adjust Clock for Daylight Savings" check box is unchecked!

Hard to believe. At least checking it again fixed the problem.

I don't know if the non-portable Sunbird has this sesitivity, if Microsoft is doing something wrong, or what.