Win 98 can’t log in

I manage a small network of about 60 clients and three Windows 2000 servers and one Unix. There are two locations connected by a point to point connection through Cisco routers. I recently had some help setting up IAS on one of the servers so some remote users could VPN through our Pix from the internet. The problem is that most of the Win 98 computers are at the remote location(the Point to point) and are now not able to log in. They either recieve the message “No domain server available” or “The domain password you supplied is not correct, or access to your logon server has been denied” I cehecked the event logs on all the servers and I don’t see anything generated by these computers.