Here is an interesting
thread discussing others who have had problems.
You are not alone. Once you get this process completed, it will be an after thought. You've just happened to purchase a Treo 650 during the release of an updated OS..aka Tiger. Tiger broke more than a few applications of mine --- including one of my favorites -- Popcorn.
FWIW, I am using iSync, iCal, Address Book with Missing Sync on Tiger. Until last night when I encountered the dreaded Kernel Panic at startup. Tomorrow, I will transfer all my data to my new 15" Powerbook just picked up today at the Apple Store.:D
-Chris