After applying SP3 to NW6 Small business we are getting the following

error,

RADIUS Server failed to load, error = 524

We get this message after entering the username and password.
We have tried changing the password, with the same error still
occuring.
If we type an incorrect password in the login box then we get error
-669
so we do not think that it is a password error.

We have watched the dstrace +AUTHEN, which says succesfull login.

any clues please as to where the problem might lie