IAS and total control chassis

I am trying to get our USR total control chassis set up to authenticate against our nt4 domain user accounts by using a win2k member server. I installed IAS and configured it.
When I try to dial in I get the specified port not open error. On the 2kserver there is also a bunch of errors “A request was received with an authenticator that is not valid from client XXXX”
Now, this is the strange part….
I can telnet in to the chassis using my domain user account and I get authorized. I go to the logs on the 2k server and there I go, I have been authorized.
I don’t really know what’s going on, anyone help?