It's a bit of a bug in the cache. Find a file named com.apple.preferencepanes.cache in the Cache folder in your Home folder's Library and delete it. Do this while System Preferences is closed though.
It's a bit of a bug in the cache. Find a file named com.apple.preferencepanes.cache in the Cache folder in your Home folder's Library and delete it. Do this while System Preferences is closed though.