RRAS on multihomed 2000 server

I have a W2K server, SP2, multihomed with internal IP’s, main NIC has gateway, RRAS installed/configured for main NIC. Client’s authenticate user & password, but get error 733 for protocol negotiation failure. Happens from inside network or externalvia cable modem and router. Reinstalled Active Directory, RRAS, DNS, WINS, DHCP. Both client and server running TCP/IP only. About to remove 2nd NIC to see if that fixes it but it will break my SQL app. Any ideas? Have searched MS and web but not much help.