Changes won't save

Hi all…

I’m having problems saving some changes on my dashboard. Specifically:

Under General Settings>User Settings>User Account Settings — If I try to turn any of these functions on or off, then click save, they revert back to what they were before I switched them.

Also, Under General Settings>Registration>Settings — If I try to turn on “Allow visitors to create passwords,” it reverts back to “Off” after I hit save.

Anyone else experiencing this? Any ideas on how to fix?

Thanks,
Kevin