Yes Windows 98 supports SHOUTcast fine. This taken directly from the the SHOUTcast online docs:
My server gets this error: "[yp_add] yp.shoutcast.com gave error (nak)" -- What's wrong with my server?
Answer: The SHOUTcast directory has refused to publish your directory entry for one of a number of reasons. Your server should have an extended error message as well which might correspond with one of the following:
* NOTE: If the extended-error message is accompanied by an IP address, check to make sure it's the same IP address and port you're running the SHOUTcast server from. If it's different, then something is changing your IP address before it gets to us. This is usually because of internet
sharing devices or software. DSL routers and cable modems typically are the culprit, as are corporate firewalls, NAT devices, or web caches. We are working on a solution for the web caches, but if any of the other devices are changing your IP, you will *have* to follow the instructions
under Connection refused: below to solve your problem. Listeners on the internet will not be able to listen to your server until you fix the problem.
See Connection refused:
* Connection refused: This typically means your server is not visible from the Internet. The usual cause is that you're located behind a firewall or NAT device (this includes internet sharing programs like Sygate, Wingate,
etc.). These devices block incoming connections to your network. You need to configure these devices to map port 8000 on the device to port 8000 on the computer running the SHOUTcast server. If you have changed the SHOUTcast DNAS configuration to have different values for the ports, you
should map that port instead. The important detail is that the SAME PORT YOU BROADCAST ON MUST BE THE PORT MAPPED FROM THE OUTSIDE. That is, you can't map port 99 to port 8000 and expect it to work. It won't.
You either have a firewall problem you're trying to use some sort of internet connection sharing software. Hope that helps.