Ok, so this took me a good two years to solve. So I figured I'd save the rest of you half of a college education if you should ever run into this.
Basically, when you try to start the Task Scheduler service under Windows 2000, it throws the following error:
Could not start the Task Scheduler service on Local Computer.
Error 1740: The endpoint is a duplicate.
What does this mean? Who cares. It has something to do with RPC endpoints. From the solution I conclude that the Task Scheduler service is doing something retarded and nobody fixed it until XP/Server 2k3.
Ultimately, the error will occur if your RPC endpoint mapper is not listening on a public interface. Now, it should be safe to re-bind the service to only listen on localhost. However, the Task Scheduler service disagrees. (I guess) it tries to connect to the public address, causing it to fail if you've re-bound the RPC endpoint mapper to localhost.
The solution sucks: bind your RPC endpoint mapper to the public address. The command to do this (assuming you used rpccfg.exe to re-bind it in the first place) is:
user $ rpccfg.exe -r
This will, of course, leave port 135 open to the world. But hey, at least you can schedule your virus scanner!