Interesting enough there are a lot of guess of how to correct this issue. The one that seems to have worked for me, is going into settings, unmounting the SD card, after it is unmounted pulling the card and reinserting it where it automatically mounts.
My issue was trying to edit contacts I would get the error and have to force close. After going through the remounting of the SD card I was able to edit the contacts.
Very weird. Try the simple steps before rebooting, uninstalling, or reinitializing the phone.