IT WORKED FOR ME! HOPE IT'S A SOLUTION FOR MOST OF US USERS OF POCKETMAC!!!
Miraculously, this afternoon I synced my Curve 8310 to my Entourage contacts and calendar AND I DIDN'T GET ANY DUPLICATE CONTACTS OR CALENDAR EVENTS!!! It was a grrrreat feeling as you all can imagine!
In fact, for the first time, PocketMac identified conflicts and asked me what to do.
Basically, I connected and started the software in a different order. First, I connected my device to my mac without having PocketMac software open on my machine. Then, obviously I started up PocketMac and simply synced. Believe me, it worked .... and I hope it works for every other user of this most bashed software.
Whether it works for you or not, please leave your comments so we can gather as much feedback as possible on this attempted fix.
Good luck to all!