🚀 go-pugleaf

I am having problems netscape 4.04 plug-in for realaudio/realvideo...
whenever I go to a page with realaudio embeded, i get error saying
"No plugin for mime type audio/x-pn-realaudio-plugin not found"
here's what i have:

1) netscape 4.04:
   preferences->applications:
   "audio/x-pn-realaudio"         application handled by "rvplayer %s"
   "audio/x-pn-realaudio-plugin"  application handled by "rvplayer %s"

   for both, "plugin" selection is not clickable. why?

2) /usr/local/netscape/plugins/libnullplugin.so
3) /usr/local/bin/rvplayer5.01

what else do I need to have/do?

thanks in advance(this is pretty urgent)

Sean