Are you activated on BES or work? If so, your admin just turned on contect protection on the device as an option. Call them up if you continue to have issues.
It means that all your stuff on the internal memory and on your media card will be encrypted. When that happens, you cannot unencrypt it without the phone doing it. The bad part is that the encryption is PIN based, so some people in the past have gotten hosed when their phone fails and they move their card to another BB. All their stuff is unreadable.
Posted from my CrackBerry at wapforums.crackberry.com