yeah it works for me on my cube (10.1.5 and before). i'm running GOTY - maybe that makes a difference? i didn't have to change anything for it to work.
or do you mean a dedicated server? when i try to run a dedicated server, classic starts up and i get the error, "This file should only be launched by Unreal Tournament. You should not open it in the Finder."
Of course, if it were to come to it, you could probly run UT in classic and then run a server. check to see if it still works that way - if it gives you the same error, then the problem is in your UT, not the pr3.