Connecting to the SMS Admin console
If you're having problems connecting to the SMS Admin console, then you may have problems with DCOM. To fix this, make sure that you have Distributed COM available on the site server. This KB article explains how to do this.
Also check that your Group Policies are OK, as you may have set the policy:
Computer Configuration\Windows Settings\Security Settings\Local Policies\Security Options\
Network Security: LAN Manager Authentication Level “Send NTLMv2 response only\refuse LM & NTLM”
This needs to be disabled in order for clients to connect.