Radius authentication on windows 2000 Oracle 8.1.7 server

[daljitsb]

I am trying to install/configure Radius authentication on windows 2000 Oracle 8.1.7 server for oracle users.

The raduis authentication is already sucessfully being used for login to network machines (OS level logins) using FUNK software

I am getting
'ORA-12641: Authentication service failed to initialize' error.

Here are the parameters from sqlnet.ora file:

#SQLNET.AUTHENTICATION_SERVICES=(NONE)
SQLNET.AUTHENTICATION_SERVICES=(RADIUS)
SQLNET.RADIUS.CHALLENGE_REPONSE=(OFF)
SQLNET.RADIUS_AUTHENTICATION=(coloexch01) # I can ping coloexch01
SQLNET.RADIUS.SECRET=(F:\oracle\ora81\Security\RADIUS.KEY)
SQLNET.AUTHENTICATION_REQUIRED=TRUE

Here is .init file setup: (database restart done after setting these parameters)

#remote_login_passwordfile = exclusive
remote_os_authent=FALSE
os_authent_prefix = ""

RADIUS.SECRET file (F:\oracle\ora81\Security\RADIUS.KEY) created with the password to match the radius server password for user 'a' (identfied externally)

I cannot login as any user not even as user 'a'. I can login as all users except as 'a' when I comment all the radius parameters in sqlnet.ora file and uncomment #SQLNET.AUTHENTICATION_SERVICES=(NONE).

What am I missing. Any help is greatly appreciated.
-D