VPN through Cisco 678

[Rockn69]

Have an NT4 server setup as a RAS server with PPTP, Cisco 678 is set up with NAT for internet access for local users and a block of static IP addresses for the PDC with RAS server. The router also has filters configured for certain services like email, NetBIOS, telnet and a few others. I try to connect from a Win98 client with a MS VPN adapter dialing in using IP assigned by server, clear text authentication setup on both ends. When I try to connect the RAS server sees there is an incoming connection, but the server never throws out a login box to the client and the connection times out with a generic "Error 650". I can see from my Cisco that protocol 47 is being used to try to connect and I am wondering if there is a filter I need to set up on the remote Cisco to allow GRE to pass through. I have tried set nat entry add, but I don't think that is the correct way to get this done. Any suggestions?? If anyone wants to look at the router config let me know.