Preferences Errors in Mavericks

I just migrated to Mavericks. I wanted to get my iCloud Keychain setup but when I go to preferences iCloud, I see the following error message: "Preferences Error Could not load iCloud preference pane."

I get the same error when I click on other Preferences, including "Internet Account", "Sharing", "Parental Controls", etc.

Some work fine, e.g. "General", "Dock", "Displays" . . .

Sometimes, when I click on the problem icons, the error is slightly different, and claims that the preference can't open because I have an intel-based mac. see below:

I have booted in safe-mode and have the same problem.

Any ideas?

Thanks,

Dan