I have finally found a solution to the MOZ 1.4 + Java plug-in upgrade problem (based on RH9).....
First I tried to use the Mozilla 1.4 (.tar.gz) version DL'ed from the ftp.mozilla.org site, together with latest JRE(ver. 1.4.2) + a sym link to gcc32 plug-in. Didn't work, resultet in hung'ups etc.
So, I removed all traces of Mozilla from the original RH9 installation (w/ rpm -e), i.e. 1.2 version.
Then I installed ver. 1.4 FROM RPM INSTEAD. The result is a fully working Mozilla 1.4 including the nice fonts, working Java etc.
You need all the rpm's (i.e nss, nspr etc.).
You can DL the rpm's from e.g.