Palm Treo 650 Using Manual page 186

You should now be able to assign time zones to your events without encountering
this problem.
If you're using Palm Desktop software:
1. On your phone, press Calendar .
2. Open the menus .
3. Select Options, and then select Preferences.
4. Uncheck the New events use time zones box (if it's checked).
5. On your computer, open Palm Desktop software and correct the wrong entries.
6. Manually enter any information you've added to your phone since the last time
you synchronized.
7. Go to the Calendar conduit dialog box, and select Desktop overwrites handheld.
8. Synchronize your phone and your computer.
9. Go to the conduit dialog box, and select Synchronize the files.
To avoid this problem in the future, do not assign time zones to your events.
Palm Desktop software does not support time zones.
184 :: Synchronization