I've had this problem several time on my Mac (with OS X Tiger), until I found out what was happening. Please keep in mind that there are several reasons why this fatal error could be occuring. The problem I had (with your fatal error symptom) occured because I opened the ShoutCast server application on my Mac (through Terminal), quit it, and opened it again. I received the error the second time I ran the application.
If this sounds like your problem, what probably happened is that when you quit the Shoutcast application in Terminal, quiting Terminal didn't really fully stop Shoucast from using its port. There are a couple ways that you could solve the problem if you're having the problem I had:
1) Restart the computer when you get the error, and try opening the server again. It should work now.
or, a more permanent solution without having to restart:
2) Next time you want to stop the server from Terminal, before quitting Terminal, use the keyboard shortcut Control-C. This really shuts down the Shoutcast server. Then quit terminal (through the Terminal menu or Command-Q).
or, if you just had the problem, and you don't want to take the time to restart the computer,
3) Open Activity Monitor (in Applications>Utilities on OS X Tiger). In the filter box, type sc_serv. The entry for the Shoutcast application should be found in the list below. Click on it, and click the red Quit Process button. Then click Force Quit. Close Activity Monitor, and run the server again. It should work this time.
Please let me know if you'd like more assistance.