Symptom
In the Time Zone section of the Date & Time pane of System Preferences, you cannot select a country within a time zone. The time zones on the map are off by plus 1 hour on the world map.
Note: This applies only when you update to Mac OS X version 10.1 from versions 10.0 to 10.0.4.
Solution
Update to Mac OS X 10.1.2 or later. For more information, see technical document 106704, "
Mac OS X: How to Update Your Software".