I had the same problem and here is how I fixed it.

Instead of copying the *.so file directly into your firefox plugin
directory, make a symbolic link to it from the firefox plugin
directory.

For example, something like this, with the appropriate directory names:
ln -s /usr/java/jre1.5.0/plugin/i386/ns7/libjavaplugin_oji.so /usr/lib/firefox-1.0/plugins/libjavaplugin_oji.so

General case:
ln -s <java-installation-directory>/libjavaplugin_oji.so <firefox-plugin-direcrotory>/libjavaplugin_oji.so

__________________________________________________ ________________
On Sun, 20 Feb 2005, nope wrote:

> On Sat, 15 Jan 2005 19:12:15 +0000 (UTC), Stephen Rafferty
> <stephen.rafferty@orange.net> wrote:
>
> >I'm in the exact same boat with this - I got java working (I use it on
> >Azureus) but it refuses to boogie with Firefox....
>
> Ditto here. No java support with firefox and fedora core 3.
>