This issue is documented in Cisco bug ID CSCse45735.
The message appears once at bootup and every time a new user logs into the device. The user is still able to login, but this message appears at every new login.
Conditions The device is configured with the aaa new-model command, but no TACACS or RADIUS group has been configured. The user could have configured aaa authentication login default none, configured aaa authentication login default local, or left the authentication group type out completely.
Either remove the aaa new-model configuration in order to stop the message from appearing on bootup and when a user logs in. Configure a RADIUS or TACACS authentication group in order to prevent the message from appearing with every new login, but note that a single message still appears on bootup. OR
Download and upgrade the Cisco IOS software to any one of these releases: