After some trial and error, I have resolved the problem. Here's what I did, but probably not all steps are necessary.
1. Deleted ~/Library/Application Support/SyncServices/Local/Compat/NSPalmCalendarSynchronizer-com.apple.Palm/*.plist
2. Removed MagicMenu.app from Login Startup list
3...
I successfully sync'ed the Treo 650 with the problem to a Mac running the latest OS and updates and also the latest Palm Desktop (but not iSync) and it worked fine.
I then sync'ed with a different computer and iSync and Missing Sync and got the same errors again.
When syncing my Treo's Databook, I'm getting this error (which appears in the console log):
2005-10-15 07:17:44.663 Translator[3648] Invoked to sync conduit com.apple.Palm:3087253469 for entityNames: anything
2005-10-15 07:17:50.608 iSync[3650] AYLogger: Logging WARNINGs
2005-10-15...
I have Bluetooth off. I also have WiFi off. No peripherals connected. The Apple second-level support person asked if placing my hand over and touching the whole trackpad wakes up the mouse. In fact, it does.
My new 17" Powerbook 1.67MHz is experiencing a similar symptom. It occurs under MacOS X 10.3.7 and 10.3.8. The cursor freezes when not in use. When I continuously move my finger over the trackpad (in circles), the cursor starts to move in 5-10 seconds. When typing, the cursor will disappear...