I can see the Appearance.prefPane is there, but i can't open, it pop up the same message.
Basically everyday is web surfing, 3D modeling and video editing, nothing special.
What should I do?
I am on 10.8.2 also. I zipped my copy of the pref pane and uploaded it here. Try to DL it and unzip, then replace your with the DL copy from me.
You might need to restart after.
If that does not work, you will need to reinstall the OS to fix it. Backup first to safe, then command-r boot and click install OS. This will not delete your data. It will take a while as the OS is 4.7GB.
Hopefully my zipped copy will do the trick for you though.