I have:
Axim x51v
Activesync 4.5.0 (build 5096)
Two PCs running XP
One PC has Outlook 2003 (sp2)
One PC has Outlook 2002 (sp3)
DST fixes applied to Axim as well
I installed AS 4.5 on one PC first along with the DST fixes on PC and Axim
Would sync up a few times before updating 2nd PC with AS 4.5 and DST fixes

The problem I am having is that there are about 3 weeks of appointments where the appointments would span two days. If I enter an appointment on one PC that lasts all day and only one day. When I then sync my Axim to my other PC, that appointment spans two days. When I correct it on that PC, the sync the Axim back up to the other PC, that appointment goes back to spaning two days.

Any ideas? I am thinking I just need to delete them and set them backup again. But I thought I did that already but for those 3 weeks, (last 3 weeks in March) but the problem still exists.

I am wondering if it's a stupid bug with this whole DST crap :-)

I would say you have a bug with the Dalight Savings Time, not your appointments. I would make sure I installed the patches correctly 1st before doing anything drastic.