MembershipCreateStatus - An unknown error occurred

How can i determine what the error is when none of the enumeration errors have been selected.  this is my switch statement
switch (localStatus)
            {
                case MembershipCreateStatus.Success:
                    lblCreateUserStatus.ForeColor = System.Drawing.Color.Green;
                    lblCreateUserStatus.Text = "The user account was successfully created!";
                    //have to create user in CMM customer object also
              ...