The change to/from DST (aka Summer time) problem is a world wide problem. Seems everyone wants their own Summer Time. Here in Oz we've got 5 different time zones -which drops back to 3 during winter.
Its a nightmare me thinks!
Micro$oft have released patches for WinXP/Vista and if you've applied them the forum time/PC will be wrong until the forum server (probably Apache on a Linux system - is that correct Adam?) catches up at what used to be the normal change over time. The server will usually have to be patched, and thats not trivial as it will require a reboot.
You just have to grit your teeth and carry on.....