I think you're mis-understanding what fsc does. fsc starts a daemon process which stays alive between calls to compile, so it doesn't have to do all the initializing work each time. You can't actually run the compile on a completely separate box unless you have a shared file system.
As Jeha says, you should specify a temp directory with -D, then the scala files you wish to compile (this is why you're getting the usage instructions - it's missing a vital piece of information).
You also need to drop the -server, as fsc picks the port it's going to run on, and tells you it the first time you run it. You'll see lines something like this:
[Temp directory: /var/folders/oj/ojMgC8mDH4uK9fM5cjlK1E+++TI/-Tmp-/scala-devel/temp]
[Port number: 54056]
[Connected to compilation daemon at port 54056]
Then, when you want to recompile, you just call the same command again (still no need to specify server ports), then finally when you're done run fsc -shutdown
see here for the man pages