Terminal services client connections

I have a windows 2000 SP1 server running Terminal Services in application mode. I have a Terminal Server (TS) 5 user CAL.
Connecting from a windows 98 machine over the Internet using VPN and then the TS client program is no problem.
Connecting from a windows 2000 machine over the Internet or LAN, no problem. Connecting from a windows 2000 machine over the Internet using a browser using the TSAC no problem.
However if I try using a windows 98 machine to connect to the TS over the Internet using a browser I get an error: ?VB Script: error connecting to terminal server: server_name? . If I try connecting using the Client program I get an error: ?server too busy?. Please help