On Nalimov, which is here:
http://www.k4it.de/index.php?topic=egtb&lang=en
there is this information: *** NEW! All 6-men tables online (except 5 vs. 1). ***
Since K+4N v K is 5 vs 1 it won't work. You would probably need to ask the author(s) as to why 5 vs 1 is not included. Maybe it is hard to program, who knows?
Does anyone know where I can find the method for mating with a king and three knights against a lone king?
Also, is there any reason why in the 6-man endgame tablebases (ie. 4 pieces plus the kings) there is no K+4N v K? I know it's a crazy situaiton, but it is certainly possible, and *might* occur. It would be easy to just say "sac one of the knights and play from there" but that does not really give the solution. (Solved in post #2)