The only reason POST or GET would matter is in to the lenght of the content (GET has a max, 256 I think). I can tell you.. I use Netscape 4.72 on my Windows 98 machine and IE 5.0 on my Macintosh system and everything works just fine for me. Did you hack your netscape? If you really need to know the method just view source with netscape and you can see it in there METHOD="????". That's one of the plus (kinda) of HTML. There is no way to hide the code from the users.
Anyhow... Check your browser configs and see if IE will work for you. I don't have any trouble posting.