When I try to add a computer to the SBS 2003 domain I receive a rpc unavailable error. When I remove ISA 2004 everything works fine. I re-installed everything last night but server is still doing the same. When ISA 2004 is running I noticed the following error in DNS log. "The DNS server could not signal the service "NAT". The error was 1168. There may be interoperability problems between the DNS service and this service."
I tried to edit the EnableRSS regsitry key, but made no difference.