I am having this issue as well and I have 1.5.6 installed.
I am having the same issue on Lowell.com. The events on the home page widget (upper right) move to previous events before they even start. I’ve done some testing, and it seems to be impacted by the end time rather than the start.
Does anyone have a fix? I have 1.5.6 installed and am using WordPress 2.9.2.
