I am trying to get the DISAPI interface to work with IIS. I just get a HTTP 500 response. If I use NWW3DCGI.EXE instead of NWW3DISAPI.DLL, everything works fine. This is under Natural 6.2
Installed it on my maschine (latest patch level) - works fine.
Did you have a look at the http server and/or windows logs?